N-CSR 1 form.htm Federated Investors, Inc.

United States

Securities and Exchange Commission

Washington, D.C. 20549

 

Form N-CSR

Certified Shareholder Report of Registered Management Investment Companies

 

 

 

 

811-5843

 

(Investment Company Act File Number)

 

Cash Trust Series, Inc.

_______________________________________________________________

 

(Exact Name of Registrant as Specified in Charter)

 

 

 

Federated Investors Funds

4000 Ericsson Drive

Warrendale, Pennsylvania 15086-7561

(Address of Principal Executive Offices)

 

 

(412) 288-1900

(Registrant's Telephone Number)

 

 

John W. McGonigle, Esquire

Federated Investors Tower

1001 Liberty Avenue

Pittsburgh, Pennsylvania 15222-3779

(Name and Address of Agent for Service)

(Notices should be sent to the Agent for Service)

 

 

 

 

 

 

Date of Fiscal Year End: 05/31/2012

 

 

Date of Reporting Period: 05/31/2012

 

 

 

 

 

 

 

Item 1. Reports to Stockholders

Annual Shareholder Report

May 31, 2012


Ticker CTGXX

Not FDIC Insured

May Lose Value

No Bank Guarantee


Federated Government Cash Series

A Portfolio of Cash Trust Series, Inc.

CONTENTS

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2012, the Fund's portfolio composition1 was as follows:

Portfolio Composition Percentage of
Total Net Assets
U.S. Government Agency Securities 39.5%
U.S. Treasury Securities 1.1%
Repurchase Agreements 60.1%
Other Assets and Liabilities — Net2 (0.7)%
TOTAL 100.0%

At May 31, 2012, the Fund's effective maturity3 schedule was as follows:

Securities With an
Effective Maturity of:		 Percentage of
Total Net Assets
1-7 Days 50.7%
8-30 Days 14.0%
31-90 Days 24.1%
91-180 Days 5.1%
181 Days or more 6.8%
Other Assets and Liabilities — Net2 (0.7)%
TOTAL 100.0%
1 See the Fund's Prospectus and Statement of Additional Information for a description of the principal types of securities in which the Fund invests.
2 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3 Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.
Annual Shareholder Report

Portfolio of Investments

May 31, 2012

Principal
Amount		 Value
GOVERNMENT AGENCIES – 39.5%
$48,070,000 1 Federal Farm Credit System Floating Rate Notes, 0.204% — 0.387%, 6/1/2012 — 8/20/2012 48,068,709
30,000,000 2 Federal Home Loan Bank System Discount Notes, 0.120% — 0.180%, 6/20/2012 — 2/12/2013 29,995,667
56,700,000 1 Federal Home Loan Bank System Floating Rate Notes, 0.179% — 0.384%, 6/1/2012 — 6/25/2012 56,686,272
272,800,000 Federal Home Loan Bank System Notes, 0.125% — 0.350%,
8/13/2012 — 6/21/2013		 272,781,176
19,000,000 2 Federal Home Loan Mortgage Corp. Discount Notes, 0.075% — 0.163%, 6/11/2012 — 10/2/2012 18,993,759
110,700,000 1 Federal Home Loan Mortgage Corp. Floating Rate Notes, 0.179% — 0.209%, 6/4/2012 — 6/18/2012 110,671,772
51,000,000 1 Federal Home Loan Mortgage Corp. Floating Rate Notes, 0.189%, 6/1/2012 — 6/6/2012 50,980,331
33,135,000 Federal Home Loan Mortgage Corp. Notes, 0.515% — 5.500%, 8/20/2012 — 11/26/2012 33,337,035
32,000,000 2 Federal National Mortgage Association Discount Notes, 0.090% — 0.100%, 6/27/2012 — 10/15/2012 31,990,770
77,220,000 1 Federal National Mortgage Association Floating Rate Notes, 0.199% — 0.400%, 6/1/2012 — 8/17/2012 77,202,109
27,048,000 Federal National Mortgage Association Notes, 0.500% — 4.250%, 9/24/2012 — 2/25/2013 27,179,908
31,100,000 1 Morgan Stanley (GTD by FDIC) Floating Rate Notes,
0.824%, 6/20/2012		 31,106,262
221,000,000 2,3,4 Straight A Funding, LLC (Unconditional Liquidity Support from Federal Financing Bank), Discount Notes, 0.180%, 7/10/2012 — 8/7/2012 220,937,115
TOTAL GOVERNMENT AGENCIES 1,009,930,885
U.S. Treasury – 1.1%
10,000,000 United States Treasury Notes, 0.625%, 6/30/2012 10,004,081
5,000,000 United States Treasury Notes, 0.750%, 3/31/2013 5,021,868
13,000,000 United States Treasury Notes, 1.375%, 9/15/2012 13,045,681
TOTAL U.S. TREASURY 28,071,630
Repurchase Agreements – 60.1%
44,812,000 Interest in $4,190,000,000 joint repurchase agreement 0.21%, dated 5/31/2012 under which Bank of America, N.A. will repurchase securities provided as collateral for $4,190,024,442 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 7/25/2041 and the market value of those underlying securities was $4,299,453,202. 44,812,000
Annual Shareholder Report
Principal
Amount		 Value
$16,000,000 5 Interest in $311,000,000 joint repurchase agreement 0.16%, dated 3/28/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $311,124,400 on 6/26/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 5/20/2042 and the market value of those underlying securities was $318,111,456. 16,000,000
40,000,000 5 Interest in $779,000,000 joint repurchase agreement 0.18%, dated 4/26/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $779,350,550 on 7/25/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 5/20/2042 and the market value of those underlying securities was $799,905,751. 40,000,000
25,000,000 5 Interest in $1,000,000,000 joint repurchase agreement 0.18%, dated 5/4/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $1,000,450,000 on 8/2/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 4/20/2042 and the market value of those underlying securities was $1,027,193,824. 25,000,000
100,000,000 Interest in $2,000,000,000 joint repurchase agreement 0.19%, dated 5/31/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $2,000,010,556 on 6/1/2012. The securities provided as collateral at the end of the period were U.S. Government Agency securities with various maturities to 7/15/2033 and the market value of those underlying securities was $2,041,808,036. 100,000,000
100,000,000 Interest in $521,000,000 joint repurchase agreement 0.20%, dated 5/31/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $521,002,894 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 6/1/2042 and the market value of those underlying securities was $532,880,986. 100,000,000
41,000,000 5 Interest in $776,000,000 joint repurchase agreement 0.21%, dated 5/15/2012 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $776,135,800 on 6/15/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 6/1/2042 and the market value of those underlying securities was $792,476,839. 41,000,000
35,000,000 5 Interest in $605,000,000 joint repurchase agreement 0.21%, dated 5/18/2012 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $605,105,875 on 6/20/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 7/15/2041 and the market value of those underlying securities was $620,551,650. 35,000,000
Annual Shareholder Report
Principal
Amount		 Value
$51,000,000 5 Interest in $1,000,000,000 joint repurchase agreement 0.13%, dated 3/12/2012 under which Deutsche Bank Securities, Inc. will repurchase securities provided as collateral for $1,000,317,778 on 6/8/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2042 and the market value of those underlying securities was $1,020,298,391. 51,000,000
78,000,000 5 Interest in $1,700,000,000 joint repurchase agreement 0.20%, dated 4/2/2012 under which Deutsche Bank Securities, Inc. will repurchase securities provided as collateral for $1,700,859,444 on 7/2/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 10/1/2049 and the market value of those underlying securities was $1,736,570,900. 78,000,000
82,000,000 5 Interest in $1,647,000,000 joint repurchase agreement 0.21%, dated 5/14/2012 under which Deutsche Bank Securities, Inc. will repurchase securities provided as collateral for $1,647,874,283 on 8/13/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 9/16/2050 and the market value of those underlying securities was $1,694,219,232. 82,000,000
129,000,000 Interest in $2,500,000,000 joint repurchase agreement 0.19%, dated 5/25/2012 under which Goldman Sachs & Co. will repurchase securities provided as collateral for $2,500,092,361 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 9/25/2045 and the market value of those underlying securities was $2,575,095,132. 129,000,000
42,000,000 5 Interest in $800,000,000 joint repurchase agreement 0.20%, dated 4/25/2012 under which ING Financial Markets LLC will repurchase securities provided as collateral for $800,400,000 on 7/24/2012. The securities provided as collateral at the end of the period held with JPMorgan & Chase Co., tri-party agent, were U.S. Government Agency securities with various maturities to 8/1/2047 and the market value of those underlying securities was $821,577,436. 42,000,000
100,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.21%, dated 5/31/2012 under which J.P. Morgan Securities LLC will repurchase securities provided as collateral for $1,000,005,833 on 6/1/2012. The securities provided as collateral at the end of the period held with JPMorgan & Chase Co., tri-party agent, were U.S. Government Agency securities with various maturities to 6/1/2042 and the market value of those underlying securities was $1,020,001,682. 100,000,000
600,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.21%, dated 5/31/2012 under which Mizuho Securities USA, Inc. will repurchase securities provided as collateral for $1,000,005,833 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 2/15/2042 and the market value of those underlying securities was $1,025,569,568. 600,000,000
Annual Shareholder Report
Principal
Amount		 Value
$26,000,000 5 Interest in $500,000,000 joint repurchase agreement 0.18%, dated 5/8/2012 under which RBC Capital Markets, LLC will repurchase securities provided as collateral for $500,072,500 on 6/7/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 5/1/2042 and the market value of those underlying securities was $510,863,217. 26,000,000
26,000,000 5 Interest in $500,000,000 joint repurchase agreement 0.21%, dated 5/17/2012 under which RBC Capital Markets, LLC will repurchase securities provided as collateral for $500,175,000 on 7/17/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 10/20/2041 and the market value of those underlying securities was $511,023,503. 26,000,000
TOTAL REPURCHASE AGREEMENTS 1,535,812,000
TOTAL INVESTMENTS — 100.7%
(AT AMORTIZED COST)6 		2,573,814,515
OTHER ASSETS AND LIABILITIES - NET — (0.7)%7 (16,792,310)
TOTAL NET ASSETS — 100% $2,557,022,205
1 Floating rate notes with current rate and next reset date shown.
2 Discount rate at time of purchase.
3 Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At May 31, 2012, these restricted securities amounted to $220,937,115, which represented 8.6% of total net assets.
4 Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Directors (the “Directors”). At May 31, 2012, these liquid restricted securities amounted to $220,937,115, which represented 8.6% of total net assets.
5 Although the repurchase date is more than seven days after the date of purchase, the Fund has the right to terminate the repurchase agreement at any time with seven-days' notice.
6 Also represents cost for federal tax purposes.
7 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2012.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1 — quoted prices in active markets for identical securities, including investment companies with daily net asset values, if applicable.

Level 2 — other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3 — significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

Annual Shareholder Report

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2012, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

FDIC  — Federal Deposit Insurance Corporation
GTD  — Guaranteed

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31 2012 2011 2010 2009 2008
Net Asset Value, Beginning of Period $1.00 $1.00 $1.00 $1.00 $1.00
Income From Investment Operations:
Net investment income 0.0001 0.0001 0.0001 0.0063 0.0324
Net realized gain on investments 0.00001 0.00001 0.0001  —   — 
TOTAL FROM INVESTMENT OPERATIONS 0.0001 0.0001 0.0002 0.0063 0.0324
Less Distributions:
Distributions from net investment income (0.0001) (0.0001) (0.0001) (0.0063) (0.0324)
Distributions from net realized gain on investments (0.0000)1 (0.0000)1 (0.0001)  —   — 
TOTAL DISTRIBUTIONS (0.0001) (0.0001) (0.0002) (0.0063) (0.0324)
Net Asset Value, End of Period $1.00 $1.00 $1.00 $1.00 $1.00
Total Return2 0.01% 0.01% 0.01% 0.64% 3.29%
Ratios to Average Net Assets:
Net expenses 0.16% 0.23% 0.31% 1.00% 1.05%
Net investment income 0.01% 0.01% 0.01% 0.60% 3.08%
Expense waiver/reimbursement3 0.90% 0.84% 0.78% 0.11% 0.01%
Supplemental Data:
Net assets, end of period (000 omitted) $2,557,022 $2,522,787 $861,225 $946,354 $850,101
1 Represents less than $0.0001.
2 Based on net asset value.
3 This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Assets and Liabilities

May 31, 2012

Assets:
Investment in repurchase agreements $1,535,812,000
Investments in securities 1,038,002,515
Total investments in securities, at amortized cost and fair value $2,573,814,515
Cash 330,172
Income receivable 700,413
Receivable for shares sold 37,603
TOTAL ASSETS 2,574,882,703
Liabilities:
Payable for investments purchased 17,000,000
Payable for shares redeemed 511,558
Payable for investment adviser fee (Note 5) 219,951
Payable for Directors'/Trustees' fees 1,493
Accrued expenses 127,496
TOTAL LIABILITIES 17,860,498
Net assets for 2,557,022,205 shares outstanding $2,557,022,205
Net Assets Consist of:
Paid-in capital $2,557,022,205
TOTAL NET ASSETS $2,557,022,205
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
($2,557,022,205÷ 2,557,022,205 shares outstanding), $0.001 par value, 12,500,000,000 shares authorized $1.00

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Operations

Year Ended May 31, 2012

Investment Income:
Interest $4,397,302
Expenses:
Investment adviser fee (Note 5) $12,948,414
Administrative fee (Note 5) 2,020,605
Custodian fees 90,954
Transfer and dividend disbursing agent fees and expenses 2,814,464
Directors'/Trustees' fees 27,863
Auditing fees 18,500
Legal fees 9,236
Portfolio accounting fees 154,490
Distribution services fee (Note 5) 2,589,683
Shareholder services fee (Note 5) 6,473,990
Account administration fee 217
Share registration costs 102,435
Printing and postage 164,681
Insurance premiums 8,638
Taxes 99,766
Miscellaneous 9,460
TOTAL EXPENSES 27,533,396
Waivers and Reimbursment (Note 5):
Waiver of investment adviser fee $(11,746,379)
Waiver of administrative fee (49,857)
Waiver of distribution services fee (2,589,683)
Waiver of shareholder services fee (6,473,990)
Waiver of account administration fee (217)
Reimbursement of transfer and dividend disbursing agent fees and expenses (2,534,832)
TOTAL WAIVERS AND REIMBURSEMENTS (23,394,958)
Net expenses 4,138,438
Net investment income 258,864
Net realized gain on investments 3,474
Change in net assets resulting from operations $262,338

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Changes in Net Assets

Year Ended May 31 2012 2011
Increase (Decrease) in Net Assets
Operations:
Net investment income $258,864 $230,640
Net realized gain on investments 3,474 7,311
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS 262,338 237,951
Distributions to Shareholders:
Distributions from net investment income (258,864) (229,294)
Distributions from net realized gain on investments (4,961) (13,200)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS (263,825) (242,494)
Share Transactions:
Proceeds from sale of shares 3,370,176,828 2,549,868,743
Proceeds from shares issued in connection with the tax-free transfer of assets from Hilliard Lyons Government Fund  —  1,606,098,314
Net asset value of shares issued to shareholders in payment of distributions declared 263,664 243,721
Cost of shares redeemed (3,336,203,917) (2,494,644,541)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS 34,236,575 1,661,566,237
Change in net assets 34,235,088 1,661,561,694
Net Assets:
Beginning of period 2,522,787,117 861,225,423
End of period $2,557,022,205 $2,522,787,117

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Notes to Financial Statements

May 31, 2012

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Government Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The primary investment objective of the Fund is current income consistent with stability of principal and liquidity.

On July 23, 2010, the Fund acquired all of the net assets of Hilliard Lyons Government Fund (the “Acquired Fund”), an open-end investment company in a tax-free reorganization in exchange for shares of the Fund, pursuant to a plan of reorganization approved by the Acquired Fund's Board of Directors on March 18, 2010. The purpose of the transaction was to combine two portfolios with comparable investment objectives and strategies. For financial reporting purposes, assets received and shares issued by the Fund were recorded at fair value; however, the cost basis of the investments received from the Acquired Fund was carried forward to align ongoing reporting of the Fund's realized and unrealized gains and losses with amounts distributable to shareholders for tax purposes.

Assuming the acquisition had been completed on June 1, 2010, the beginning of the annual reporting period of the Fund, the Fund's pro forma results of operations for the year ended May 31, 2011, are as follows:

Net investment income* $205,605
Net realized and unrealized gain on investments $ 7,311
Net increase in net assets resulting from operations $212,916
* Net investment income includes $49,429 of pro forma additional expenses.

Because the combined investment portfolios have been managed as a single integrated portfolio since the acquisition was completed, it is not practicable to separate the amounts of revenue and earnings of the Acquired Fund that has been included in the Fund's Statement of Operations as of May 31, 2011. For every one share exchanged, a shareholder of Hilliard Lyons Government Fund received one share of the Fund. The Fund received net assets from the Acquired Fund as the result of the tax-free reorganization as follows:

Shares of the
Fund Issued		 Acquired Fund
Net Assets
Received		 Net Assets
of the Fund
Immediately
Prior to
Combination		 Net Assets
of the Fund
Immediately
After
Combination
1,606,098,314 $1,606,098,314 $964,260,498 $2,570,358,812
Annual Shareholder Report

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate market value, the fair value of the portfolio securities will be determined under procedures established by and under the general supervision of the Directors.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

Annual Shareholder Report

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective interest rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2012, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2012, tax years 2009 through 2012 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed Delivery Transactions

The Fund may engage in when-issued or delayed delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated.

3. capital stock

The following table summarizes share activity:

Year Ended May 31 2012 2011
Shares sold 3,370,176,828 2,549,868,743
Proceeds from shares issued in connection with the tax-free transfer of assets from Hilliard Lyons Government Fund _ 1,606,098,314
Shares issued to shareholders in payment of distributions declared 263,664 243,721
Shares redeemed (3,336,203,917) (2,494,644,541)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS 34,236,575 1,661,566,237

Annual Shareholder Report

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2012 and 2011, was as follows:

2012 2011
Ordinary income1 $263,825 $242,494
1 For tax purposes, short-term capital gain distributions are treated as ordinary income distributions.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

Federated Investment Management Company is the Fund's investment adviser (the “Adviser”). The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the Adviser voluntarily waived $11,746,379 of its fee. In addition, for the year ended May 31, 2012, an affiliate of the Adviser reimbursed $2,534,832 of transfer and dividend disbursing agent fees and expenses.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. The fee paid to FAS is based on the average aggregate daily net assets of certain Federated funds as specified below:

Administrative Fee Average Aggregate Daily Net Assets
of the Federated Funds
0.150% on the first $5 billion
0.125% on the next $5 billion
0.100% on the next $10 billion
0.075% on assets in excess of $20 billion

The administrative fee received during any fiscal year shall be at least $150,000 per portfolio and $40,000 per each additional class of Shares. Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the net fee paid to FAS was 0.076% of the daily net assets of the Fund. FAS waived $ 49,857 of its fee.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, FSC voluntarily waived its entire fee of $2,589,683. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Annual Shareholder Report

Shareholder Services Fee

The Fund may pay fees (“Service Fees”) up to 0.25% of the average daily net assets of the Fund's Shares to financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for Service Fees. For the year ended May 31, 2012, unaffiliated third-party financial intermediaries waived $6,473,990 of shareholder services fees and $217 of account administration fees. These waivers can be modified or terminated at any time.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and its affiliates (which may include FSC, FAS and FSSC) have voluntarily agreed to waive their fees and/or reimburse expenses so that the total annual fund operating expenses (as shown in the financial highlights) paid by the Fund (after the voluntary waivers and reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2013; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of the above companies.

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the program was not utilized.

Annual Shareholder Report

8. RECENT ACCOUNTING PRONOUNCEMENTS

In April 2011, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2011-03, “Reconsideration of Effective Control for Repurchase Agreements.” This ASU amends FASB Accounting Standards Codification (ASC) Topic 860, “Transfers and Servicing”; specifically the criteria required to determine whether a repurchase agreement and similar agreements should be accounted for as sales of financial assets or secured borrowings with commitments. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-03 is not expected to have a material impact on the Fund's financial statements and the accompanying notes, net assets or results of operations.

In addition, in May 2011, FASB released ASU No. 2011-04, “Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” This ASU amends FASB ASC Topic 820, “Fair Value Measurement,” to establish common requirements for measuring fair value and for disclosing information about fair value measurements in accordance with GAAP. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-04 is not expected to have a material impact on the Fund's financial statements and the accompanying notes.

Annual Shareholder Report

Report of Independent Registered Public Accounting Firm

TO THE BOARD OF TRUSTEES OF Cash TRUST SERIES, INC. AND SHAREHOLDERS Of Federated government cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Government Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2012, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2012, by correspondence with the custodian and others or by other appropriate auditing procedures where replies from others were not received. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Government Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2012, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 24, 2012

Annual Shareholder Report

Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or shareholder services fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2011 to May 31, 2012.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Annual Shareholder Report

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

Beginning
Account Value
12/1/2011		 Ending
Account Value
5/31/2012		 Expenses Paid
During Period1,2
Actual $1,000 $1,000.05 $0.90
Hypothetical (assuming a 5% return
before expenses)		 $1,000 $1,024.10 $0.91
1 Expenses are equal to the Fund's annualized net expense ratio of 0.18%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).
2 Actual and Hypothetical expenses paid during the period utilizing the Fund's current annualized net expense ratio of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.
Annual Shareholder Report

Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2011, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 43 investment companies (comprising 134 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held and Previous Position(s)
John F. Donahue*
Birth Date: July 28, 1924
Director
Began serving: May 1989		 Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee.

Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.
J. Christopher Donahue*
Birth Date: April 11, 1949
President and Director
Began serving: May 1989		 Principal Occupations: Principal Executive Officer and President of the Federated Fund Family; Director or Trustee of some of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company.

Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.
Annual Shareholder Report

INDEPENDENT DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Nicholas P. Constantakis, CPA
Birth Date: September 3, 1939
Director
Began serving: February 1998		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorship Held: Director, Chairman of the Audit Committee, and member of the Compensation Committee, Michael Baker Corporation (architecture, engineering and construction services).

Previous Position: Partner, Andersen Worldwide SC.

Qualifications: Public accounting and director experience.
John F. Cunningham
Birth Date: March 5, 1943
Director
Began serving: January 1999		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorships Held: Chairman, President and Chief Executive Officer, Cunningham & Co., Inc. (strategic business consulting); Trustee Associate, Boston College.

Previous Positions: Director, Redgate Communications and EMC Corporation (computer storage systems); Chairman of the Board and Chief Executive Officer, Computer Consoles, Inc.; President and Chief Operating Officer, Wang Laboratories; Director, First National Bank of Boston; Director, Apollo Computer, Inc.

Qualifications: Business management and director experience.
Maureen Lally-Green
Birth Date: July 5, 1949
Director
Began serving: August 2009		 Principal Occupations: Director or Trustee of the Federated Fund Family; Director, Office of Church Relations, Diocese of Pittsburgh; Adjunct Professor of Law, Duquesne University School of Law.

Other Directorships Held: Director, Auberle; Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director, Ireland Institute of Pittsburgh; Chair and Director, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Saint Thomas More Society, Allegheny County.

Previous Position: Pennsylvania Superior Court Judge.

Qualifications: Legal and director experience.
Peter E. Madden
Birth Date: March 16, 1942
Director
Began serving: August 1991		 Principal Occupation: Director or Trustee, and Chairman of the Board of Directors or Trustees, of the Federated Fund Family.

Previous Positions: Representative, Commonwealth of Massachusetts General Court; President, Chief Operating Officer and Director, State Street Bank and Trust Company and State Street Corporation (retired); Director, VISA USA and VISA International; Chairman and Director, Massachusetts Bankers Association; Director, Depository Trust Corporation; Director, The Boston Stock Exchange.

Qualifications: Business management, mutual fund services and director experience.
Annual Shareholder Report
Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Charles F. Mansfield, Jr.
Birth Date: April 10, 1945
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant.

Previous Positions: Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President, DVC Group, Inc. (marketing, communications and technology).

Qualifications: Banking, business management, education and director experience.
Thomas M. O'Neill
Birth Date: June 14, 1951
Director
Began serving: October 2006		 Principal Occupations: Director or Trustee, Vice Chairman of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting).

Other Directorships Held: Board of Overseers, Children's Hospital of Boston; Visiting Committee on Athletics, Harvard College; Board of Directors, Medicines for Humanity; Board of Directors, The Golisano Children's Museum of Naples, Florida.

Previous Positions: Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); Director, Midway Pacific (lumber).

Qualifications: Business management, mutual fund, director and investment experience.
John S. Walsh
Birth Date: November 28, 1957
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee, Chairman of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc.

Previous Position: Vice President, Walsh & Kelly, Inc.

Qualifications: Business management and director experience.
Annual Shareholder Report

OFFICERS

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years
and Previous Position(s)
John W. McGonigle
Birth Date: October 26, 1938
EXECUTIVE VICE PRESIDENT AND SECRETARY
Began serving: May 1989		 Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc.

Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Richard A. Novak
Birth Date: December 25, 1963
TREASURER
Began serving: January 2006		 Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.

Previous Positions: Controller of Federated Investors, Inc.; Vice President, Finance of Federated Services Company; held various financial management positions within The Mercy Hospital of Pittsburgh; Auditor, Arthur Andersen & Co.
Richard B. Fisher
Birth Date: May 17, 1923
VICE CHAIRMAN
Began serving: August 2002		 Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp.

Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.
Brian P. Bouda
Birth Date: February 28, 1947
CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT
Began serving: August 2004		 Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin.
Deborah A. Cunningham
Birth Date: September 15, 1959
CHIEF INVESTMENT OFFICER
Began serving: May 2004		 Principal Occupations: Deborah A. Cunningham has been the Fund's Portfolio Manager since January 1994. Ms. Cunningham was named Chief Investment Officer of money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Susan R. Hill
Birth Date: June 20, 1963
VICE PRESIDENT
Began serving: June 2012		 Principal Occupations: Susan R. Hill has been the Fund's Portfolio Manager since January 1994. She is Vice President of the Corporation. Ms. Hill joined Federated in 1990 and has been a Senior Portfolio Manager since 2003 and a Senior Vice President of the Fund's Adviser since 2005. Ms. Hill was a Portfolio Manager from 1994 until 2003 and served as Vice President of the Fund's Adviser from 1997 until 2004 and an Assistant Vice President of the Fund's Adviser from 1994 until 1997. Ms. Hill has received the Chartered Financial Analyst designation and holds an M.S. in Industrial Administration from Carnegie Mellon University.

Annual Shareholder Report

Evaluation and Approval of Advisory Contract – May 2012

FEDERATED GOVERNMENT CASH SERIES (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2012 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies exist, whether they have been shared with a fund and its shareholders; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent to which the Board members are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. Consistent with these judicial decisions, the Board also considered management fees (including any components thereof) charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

Annual Shareholder Report

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

Annual Shareholder Report

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant, given the high degree of competition in the mutual fund business. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a generally reliable indication of what consumers have found to be reasonable in the precise marketplace in which the Fund competes. In this regard, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes; different associated costs; different portfolio management techniques made necessary by different cash flows; and portfolio manager time spent in review of securities pricing. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory contracts.

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn assisted the Board in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups are relevant in judging the reasonableness of proposed fees.

For the one-year period covered by the Evaluation, the Fund's performance was above the median of the relevant peer group.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be Annual Shareholder Report

competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution or elimination of these voluntary waivers.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, although they may apply consistent allocation processes, the inherent difficulties in allocating costs (and the unavoidable arbitrary aspects of that exercise) and the lack of consensus on how to allocate those costs may render such allocation information unreliable. The allocation information was considered in the analysis by the Board but was determined to be of limited use.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer noted the limited availability of such information, but nonetheless concluded that Federated's profit margins did not appear to be excessive.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies, should they exist) were likely to be enjoyed by the fund complex as a whole. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size. The Senior Officer did not recommend institution of breakpoints in pricing Federated's fund advisory services at this time.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual fee rate and other expenses of the Fund with the Adviser and was satisfied that the overall expense structure of the Fund remained competitive.

The Senior Officer noted that, considering the totality of the circumstances, and all of the factors referenced within his Evaluation, he had concluded that, subject to comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds was Annual Shareholder Report

reasonable and that Federated appeared to provide appropriate advisory and administrative services to the Fund for the fees paid. Under these circumstances, no changes were recommended to, and no objection was raised to, the continuation of the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

Annual Shareholder Report

Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available from Federated's website at FederatedInvestors.com. To access this information from the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Proxy Voting Record Report (Form N-PX).” Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information from the “Products” section of Federated's website at FederatedInvestors.com. From the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Form N-Q.”

Annual Shareholder Report

Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Government Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551204



28564 (7/12)

Federated is a registered trademark of Federated Investors, Inc.
2012  © Federated Investors, Inc.

Annual Shareholder Report

May 31, 2012


Ticker CMSXX

Not FDIC Insured

May Lose Value

No Bank Guarantee


Federated Municipal Cash Series

A Portfolio of Cash Trust Series, Inc.

CONTENTS

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2012, the Fund's portfolio composition1 was as follows:

Portfolio Composition Percentage of
Total Net Assets
Variable Rate Demand Instruments 77.2%
Municipal Notes 21.6%
Commercial Paper 0.8%
Other Assets and Liabilities — Net2 0.4%
TOTAL 100.0%

At May 31, 2012, the Fund's effective maturity3 schedule was as follows:

Securities with an
Effective Maturity of:		 Percentage of
Total Net Assets
1-7 Days 76.3%
8-30 Days 4.9%
31-90 Days 4.6%
91-180 Days 6.4%
181 Days or more 7.4%
Other Assets and Liabilities — Net2 0.4%
TOTAL 100.0%
1 See the Fund's Prospectus and Statement of Additional Information for a description of these investments.
2 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3 Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.
Annual Shareholder Report

Portfolio of Investments

May 31, 2012

Principal
Amount		 Value
SHORT-TERM MUNICIPALS – 99.6%1,2
Alabama – 0.3%
$1,178,000 Birmingham, AL IDA, IDRBs (Series 1999) Weekly VRDNs (Glasforms, Inc.)/(Wells Fargo Bank, N.A. LOC), 0.220%, 6/7/2012 1,178,000
Arizona – 9.5%
1,055,000 Casa Grande, AZ IDA, (Series 2002A) Weekly VRDNs (Price Cos., Inc.)/(Bank of America N.A. LOC), 0.490%, 6/7/2012 1,055,000
7,221,000 Flagstaff, AZ IDA, (Series 1999) Weekly VRDNs (Joy Cone Co.)/(Citizens Bank of Pennsylvania LOC), 0.280%, 6/7/2012 7,221,000
3,200,000 Maricopa County, AZ, IDA MFH, (Series 2008: Village at Sun Valley Apartments) Weekly VRDNs (Western Sun Valley, LP)/(FHLMC LOC), 0.260%, 6/7/2012 3,200,000
5,610,000 Maricopa County, AZ, IDA, (Series 1999) Weekly VRDNs (Redman Homes, Inc.)/(Wells Fargo & Co. LOC), 0.270%, 6/7/2012 5,610,000
965,000 Phoenix, AZ IDA, (Series 2000) Weekly VRDNs (MechoShade West, Inc.)/(JPMorgan Chase Bank, N.A. LOC), 0.380%, 6/7/2012 965,000
2,100,000 Pinal County, AZ IDA, (Series 2002) Weekly VRDNs (D.A. Holdings LLC)/(Wells Fargo Bank, N.A. LOC), 0.280%, 6/7/2012 2,100,000
6,750,000 Pinal County, AZ IDA, (Series 2002) Weekly VRDNs (Milky Way Dairy LLC)/(Rabobank Nederland NV, Utrecht LOC), 0.280%, 6/7/2012 6,750,000
3,630,000 Pinal County, AZ IDA, (Series 2005) Weekly VRDNs (Three C Eloy LLC)/(CoBank, ACB LOC), 0.320%, 6/7/2012 3,630,000
1,175,000 Pinal County, AZ IDA, (Series 2006) Weekly VRDNs (Three C Eloy LLC)/(CoBank, ACB LOC), 0.320%, 6/7/2012 1,175,000
3,400,000 Pinal County, AZ IDA, (Series 2007) Weekly VRDNs (Artistic Paver Mfg. Phoenix, Inc.)/(SunTrust Bank LOC), 0.480%, 6/6/2012 3,400,000
2,135,000 3,4 Salt River Project, AZ Agricultural Improvement & Power District, ROCs (Series 12276) Weekly VRDNs (Citibank NA, New York LIQ), 0.210%, 6/7/2012 2,135,000
6,500,000 Show Low, AZ IDA, (Series 2006) Weekly VRDNs (Snowflake White Mountain Power LLC)/(JPMorgan Chase Bank, N.A. LOC), 0.320%, 6/7/2012 6,500,000
TOTAL 43,741,000
California – 1.8%
3,000,000 Big Bear Lake, CA IDRB, (Series 1993A) Weekly VRDNs (Southwest Gas Corp.)/(KBC Bank N.V. LOC), 0.650%, 6/6/2012 3,000,000
3,000,000 California State, (Series A-2), 2.00% RANs, 6/26/2012 3,003,275
2,165,000 Oxnard, CA IDFA, (Series 2004) Weekly VRDNs (J. Harris Industrial Water Treatment, Inc.)/(City National Bank LOC), 1.200%, 6/7/2012 2,165,000
TOTAL 8,168,275
Annual Shareholder Report
Principal
Amount		 Value
Colorado – 3.0%
$3,300,000 Colorado Agricultural Development Authority, (Series 2006) Weekly VRDNs (Monte Vista Dairy, LLC)/(Bank of the West, San Francisco, CA LOC), 0.480%, 6/7/2012 3,300,000
570,000 Colorado HFA (Class I Bonds), (Series 2000A) Weekly VRDNs (New Belgium Brewing Co., Inc.)/(Wells Fargo Bank, N.A. LOC), 0.330%, 6/7/2012 570,000
9,990,000 3,4 Denver, CO City & County Airport Authority, SPEARs (Series DBE-485), 0.40% TOBs (GTD by Deutsche Bank AG)/(Deutsche Bank AG LIQ), Optional Tender 6/14/2012 9,990,000
TOTAL 13,860,000
Florida – 4.9%
620,000 3,4 Clipper Tax-Exempt Certificates Trust (Florida AMT)/(Series 2009-75) Weekly VRDNs (GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.300%, 6/7/2012 620,000
6,000,000 Collier County, FL IDA, (Series 2005) Weekly VRDNs (Ave Maria Utility Company)/(SunTrust Bank LOC), 0.670%, 6/6/2012 6,000,000
10,000,000 Miami-Dade County, FL Transit System, (Series 2011), 0.80% BANs, 11/21/2012 10,000,000
6,140,000 UCF Health Facilities Corp., Capital Improvement Revenue Bonds (Series 2007) Weekly VRDNs (UCF Health Sciences Campus at Lake Nona)/(Fifth Third Bank, Cincinnati LOC), 0.310%, 6/1/2012 6,140,000
TOTAL 22,760,000
Georgia – 11.2%
5,500,000 3,4 Atlanta, GA Water & Wastewater, Lehman FR/RI-K2 Floater Certificates (Series 2006) Weekly VRDNs (Assured Guaranty Municipal Corp. INS)/(Citibank NA, New York LIQ), 0.300%, 6/7/2012 5,500,000
3,350,000 Atlanta, GA, Urban Residential Finance Authority, (Series 1995) Weekly VRDNs (West End Housing Development)/(FNMA LOC), 0.330%, 6/7/2012 3,350,000
250,000 Bartow County, GA Development Authority, (Series 2002) Weekly VRDNs (Somerset Cove Apartments, LP)/(Compass Bank, Birmingham LOC), 1.360%, 6/7/2012 250,000
1,500,000 Burke County, GA Development Authority, PCR (Series 1992) Daily VRDNs (Georgia Power Co.), 0.240%, 6/1/2012 1,500,000
2,500,000 Clayton County, GA Development Authority, (Series 2000) Weekly VRDNs (Anasteel & Supply Company LLC)/(Branch Banking & Trust Co. LOC), 0.240%, 6/7/2012 2,500,000
5,000,000 DeKalb County, GA, 1.00% TANs, 12/28/2012 5,017,994
5,375,000 Gainesville and Hall County, GA Development Authority, (Series 2002) Weekly VRDNs (Fieldale Farms Corp.)/(Rabobank Nederland NV, Utrecht LOC), 0.250%, 6/7/2012 5,375,000
18,000,000 3,4 Georgia State HFA, MERLOTS (Series 2006-B11) Weekly VRDNs (Wells Fargo Bank, N.A. LIQ), 0.250%, 6/6/2012 18,000,000
1,000,000 Kennesaw, GA Development Authority, (Series 2004) Weekly VRDNs (Walton Ridenour Apts)/(FHLB of Atlanta LOC), 0.240%, 6/6/2012 1,000,000
Annual Shareholder Report
Principal
Amount		 Value
$4,000,000 Pike County, GA Development Authority, (Series 2003) Weekly VRDNs (Southern Mills, Inc.)/(Bank of America N.A. LOC), 0.490%, 6/6/2012 4,000,000
3,500,000 Wayne County, GA Development Authority, (Series 2000) Weekly VRDNs (Republic Services of Georgia)/(Wells Fargo Bank, N.A. LOC), 0.330%, 6/6/2012 3,500,000
1,600,000 Willacoochee, GA Development Authority, (Series 1997) Weekly VRDNs (Langboard, Inc.)/(FHLB of Atlanta LOC), 0.280%, 6/7/2012 1,600,000
TOTAL 51,592,994
Hawaii – 0.4%
2,000,000 Hawaii State Airport System, (Series 2011), 2.00% Bonds, 7/1/2012 2,002,378
Illinois – 8.3%
4,900,000 Chicago, IL O'Hare International Airport, Special Facility Revenue Bonds (Series 1990) Weekly VRDNs (Compagnie Nationale Air France Project)/(Societe Generale, Paris LOC), 0.330%, 6/6/2012 4,900,000
1,435,000 Chicago, IL, (Series 2001) Weekly VRDNs (J.M.B. Moesle LLC)/(BMO Harris Bank, N.A. LOC), 0.490%, 6/7/2012 1,435,000
1,295,000 Illinois Development Finance Authority IDB Weekly VRDNs (T&D Investments LLC)/(U.S. Bank, N.A. LOC), 0.450%, 6/7/2012 1,295,000
2,525,000 Illinois Development Finance Authority IDB, (Series 1997) Weekly VRDNs (Tempco Electric Heater Corp.)/(JPMorgan Chase Bank, N.A. LOC), 0.440%, 6/7/2012 2,525,000
1,000,000 Illinois Development Finance Authority IDB, (Series 2001) Weekly VRDNs (Apogee Enterprises, Inc.)/(Comerica Bank LOC), 0.430%, 6/7/2012 1,000,000
3,000,000 Illinois Development Finance Authority, (Series 2002) Weekly VRDNs (Kasbergen Family Living Trust)/(Bank of the West, San Francisco, CA LOC), 0.480%, 6/7/2012 3,000,000
2,900,000 Illinois Finance Authority, (Series 2008) Weekly VRDNs (Jasper Meats, Inc.)/(BMO Harris Bank, N.A. LOC), 0.300%, 6/7/2012 2,900,000
3,000,000 Illinois State, (Series 2012), 2.00% Bonds, 2/1/2013 3,022,815
3,300,000 Lockport, IL IDA, (Series 1990) Weekly VRDNs (Panduit Corp.)/(Fifth Third Bank, Cincinnati LOC), 0.340%, 6/6/2012 3,300,000
5,800,000 Orland Park, IL IDA, (Series 1996) Weekly VRDNs (Panduit Corp.)/(Fifth Third Bank, Cincinnati LOC), 0.340%, 6/6/2012 5,800,000
9,200,000 Will County, IL, (Series 2007) Weekly VRDNs (University of St. Francis)/(Fifth Third Bank, Cincinnati LOC), 0.310%, 6/1/2012 9,200,000
TOTAL 38,377,815
Indiana – 2.0%
1,500,000 Indiana Development Finance Authority, EDRB (Series 2002) Weekly VRDNs (Vreba-Hoff Dairy Leasing LLC)/(Wells Fargo Bank, N.A. LOC), 0.330%, 6/7/2012 1,500,000
2,000,000 Indiana State Finance Authority Environmental Revenue, IDRB (Series 2011) Weekly VRDNs (Modern Forge Indiana LLC)/(Fifth Third Bank, Cincinnati LOC), 0.350%, 6/1/2012 2,000,000
Annual Shareholder Report
Principal
Amount		 Value
$5,500,000 Indianapolis, IN MFH, (Series 2007A: Forest Ridge Apartments) Weekly VRDNs (Pedcor Investments-2006-LXXXVIII LP)/(RBS Citizens Bank N.A. LOC), 0.280%, 6/7/2012 5,500,000
TOTAL 9,000,000
Iowa – 1.7%
7,700,000 Iowa Finance Authority, (Series 2006) Weekly VRDNs (Ag Real Estate Iowa One, LP)/(Rabobank Nederland NV, Utrecht LOC), 0.300%, 6/7/2012 7,700,000
Kansas – 1.0%
2,723,000 3,4 Clipper Tax-Exempt Certificates Trust (Kansas-AMT)/(Series 2009-11) Weekly VRDNs (Sedgwick & Shawnee Counties, KS)/(GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.300%, 6/7/2012 2,723,000
1,930,000 Wyandotte County, KS, (Series 1999) Weekly VRDNs (Shor-Line)/(U.S. Bank, N.A. LOC), 0.260%, 6/6/2012 1,930,000
TOTAL 4,653,000
Kentucky – 0.6%
500,000 Henderson County, KY, (Series 1996A) Weekly VRDNs (Gibbs Die Casting Corp.)/(Fifth Third Bank, Cincinnati LOC), 0.530%, 6/7/2012 500,000
2,100,000 Kentucky Housing Corp., (Series 2007) Weekly VRDNs (Arbors of Madisonville Apartments LP)/(U.S. Bank, N.A. LOC), 1.150%, 6/7/2012 2,100,000
TOTAL 2,600,000
Louisiana – 0.6%
2,800,000 Port of New Orleans, LA, (Series 2000) Weekly VRDNs (New Orleans Steamboat Co.)/(FHLB of Dallas LOC), 0.330%, 6/7/2012 2,800,000
Maine – 3.6%
2,190,000 Dover-Foxcroft, ME, (Series 2005) Weekly VRDNs (Pleasant River Lumber Co.)/(Wells Fargo Bank, N.A. LOC), 0.300%, 6/6/2012 2,190,000
14,290,000 Maine Finance Authority, (Series 2002) Weekly VRDNs (The Jackson Laboratory)/(Bank of America N.A. LOC), 0.400%, 6/7/2012 14,290,000
TOTAL 16,480,000
Massachusetts – 0.2%
1,000,000 Massachusetts Development Finance Agency, (Series 2004), 0.45% CP (Nantucket Electric Co.)/(GTD by Massachusetts Electric Co.), Mandatory Tender 6/28/2012 1,000,000
Minnesota – 2.7%
12,500,000 Eden Prairie, MN MFH, (Series 2003-A) Weekly VRDNs (Eden Prairie, MN Leased Housing Associates LLP)/(Bank of America N.A. LOC), 0.500%, 6/1/2012 12,500,000
50,000 Plymouth, MN Weekly VRDNs (Nuaire, Inc.)/(Wells Fargo Bank, N.A. LOC), 0.530%, 6/7/2012 50,000
TOTAL 12,550,000
Annual Shareholder Report
Principal
Amount		 Value
Multi-State – 7.8%
$2,000,000 3,4 Blackrock MuniYield Quality Fund III, Inc., (3,564 Series W-7 VRDP Shares), 0.320%, 6/7/2012 2,000,000
935,000 3,4 Clipper Tax-Exempt Certificates Trust (Multi-State AMT)/(Series 2009-68) Weekly VRDNs (GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.330%, 6/7/2012 935,000
1,588,000 3,4 Clipper Tax-Exempt Certificates Trust (Multi-State AMT)/(Series 2009-78) Weekly VRDNs (State Street Bank and Trust Co. LIQ), 0.330%, 6/7/2012 1,588,000
6,700,000 3,4 Nuveen Dividend Advantage Municipal Fund 2, Weekly VRDPs (Series 2)/(GTD by Deutsche Bank AG), 0.310%, 6/7/2012 6,700,000
5,000,000 3,4 Nuveen Investment Quality Municipal Fund, Inc., Weekly VRDPs (2,118 Series 1)/GTD by Barclays Bank PLC), 0.330%, 6/7/2012 5,000,000
5,000,000 3,4 Nuveen Municipal Market Opportunity Fund, Inc., Weekly VRDPs (Series 1)/(GTD by Deutsche Bank AG), 0.240% 6/7/2012 5,000,000
5,000,000 3,4 Nuveen Premier Municipal Income Fund, Inc., Weekly VRDPs (1.277 Series 1)/(GTD by Barclays Bank PLC), 0.330%, 6/7/2012 5,000,000
10,000,000 3,4 Nuveen Premium Income Municipal Fund 4, Inc., Weekly VRDPs (Series 1)/(GTD by JPMorgan Chase Bank, N.A.), 0.290%, 6/7/2012 10,000,000
TOTAL 36,223,000
New Jersey – 3.0%
2,500,000 Edgewater, NJ, 1.50% BANs, 12/6/2012 2,507,628
3,957,860 Evesham Township, NJ, 1.50% BANs, 10/25/2012 3,969,924
3,181,000 Medford Township, NJ, (Series 2011A), 1.50% BANs, 7/10/2012 3,183,114
4,034,000 Saddle River, NJ, 1.50% BANs, 8/3/2012 4,039,174
TOTAL 13,699,840
New York – 11.0%
4,118,330 Brasher Falls, NY CSD, 1.75% BANs, 6/29/2012 4,120,668
765,000 Cattaraugus County, NY IDA, (Series 1999A) Weekly VRDNs (Gernatt Asphalt Products, Inc.)/(Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.330%, 6/7/2012 765,000
1,050,000 Cayuga County, NY IDA, (Series 1998) Weekly VRDNs (NFR Northeast, Inc.)/(Citizens Bank of Pennsylvania LOC), 0.330%, 6/6/2012 1,050,000
1,480,000 Erie County, NY IDA, IDRB (Series 1994) Weekly VRDNs (Servotronics, Inc.)/(Bank of America N.A. LOC), 0.460%, 6/7/2012 1,480,000
1,700,000 Madison County, NY IDA, (Series A) Weekly VRDNs (Owl Wire and Cable)/(Key Bank, N.A. LOC), 0.360%, 6/6/2012 1,700,000
1,300,000 New York City, NY IDA, IDRBs (Series 2003) Weekly VRDNs (Novelty Crystal Corp.)/(TD Bank, N.A. LOC), 0.340%, 6/7/2012 1,300,000
12,900,000 New York City, NY, (Fiscal 2008 Subseries J-11) Weekly VRDNs (KBC Bank N.V. LIQ), 0.350%, 6/7/2012 12,900,000
20,000,000 3,4 Nuveen New York Investment Quality Municipal Fund, Inc., Weekly VRDPs (Series 1)/ (GTD by Citibank NA, New York), 0.300%, 6/7/2012 20,000,000
Annual Shareholder Report
Principal
Amount		 Value
$7,500,000 Oyster Bay, NY, (Series 2012A), 2.50% BANs, 3/8/2013 7,617,404
TOTAL 50,933,072
Ohio – 9.9%
3,000,000 Ashtabula County, OH, 1.00% BANs, 5/23/2013 3,011,616
8,500,000 Bath, OH Local School District, 1.25% BANs, 11/15/2012 8,530,782
1,345,000 Brunswick, OH, 1.15% BANs, 11/14/2012 1,348,028
5,000,000 Butler County, OH, 0.50% BANs, 8/2/2012 5,000,000
5,500,000 Cleveland, OH, Subordinated Water Revenue Notes (Series 2011), 1.00% BANs, 7/26/2012 5,504,108
1,500,000 Lancaster, OH Port Authority, (Series 2008) Gas Supply Revenue Weekly VRDNs (Royal Bank of Canada, Montreal LIQ), 0.180%, 6/7/2012 1,500,000
1,100,000 Mayfield, OH, 1.125% BANs, 8/30/2012 1,100,871
3,095,000 Montgomery County, OH, (Series 2006A) Weekly VRDNs (Cambridge Commons Apartments)/(FHLB of Indianapolis LOC), 0.200%, 6/7/2012 3,095,000
1,000,000 Oakwood City, OH, 1.125% BANs, 3/7/2013 1,001,702
1,000,000 Ohio HFA, (Series I) Weekly VRDNs (GNMA COL)/(Citibank NA, New York LIQ), 0.230%, 6/6/2012 1,000,000
3,500,000 Ohio HFA, (Series J) Weekly VRDNs (GNMA COL)/(State Street Bank and Trust Co. LIQ), 0.220%, 6/6/2012 3,500,000
5,000,000 Ohio State Higher Educational Facility Commission, (Series 2008B) Weekly VRDNs (University Hospitals Health System, Inc.)/(RBS Citizens Bank N.A. LOC), 0.230%, 6/6/2012 5,000,000
1,500,000 Parma Heights, OH, 1.25% BANs, 8/1/2012 1,501,239
2,000,000 Ravenna, OH, 1.75% BANs, 10/25/2012 2,005,952
1,615,000 Sandusky, OH, 1.25% BANs, 10/11/2012 1,618,173
1,000,000 South Euclid, OH, (Series B), 1.25% BANs, 9/26/2012 1,002,545
TOTAL 45,720,016
Oregon – 0.9%
4,000,000 Oregon State Housing and Community Services Department, (2008 Series C) Weekly VRDNs (KBC Bank N.V. LIQ), 0.630%, 6/7/2012 4,000,000
Pennsylvania – 2.1%
7,860,000 Pennsylvania State IDA, 3.00% Bonds, 1/1/2013 7,970,328
1,870,000 Philadelphia, PA Airport System, (Series B), 2.00% Bonds, 6/15/2012 1,870,940
TOTAL 9,841,268
South Carolina – 1.0%
4,480,000 South Carolina Jobs-EDA, (Series 2007) Weekly VRDNs (ACI Industries LLC)/(Bank of America N.A. LOC), 0.330%, 6/7/2012 4,480,000
125,000 South Carolina Jobs-EDA, (Series 2007A) Weekly VRDNs (Woodhead LLC)/(FHLB of Atlanta LOC), 0.280%, 6/7/2012 125,000
TOTAL 4,605,000
Annual Shareholder Report
Principal
Amount		 Value
Tennessee – 3.7%
$10,000,000 Metropolitan Government Nashville & Davidson County, TN IDB, (Series 2006) Weekly VRDNs (The Fountains Apartments, LLC)/(Fifth Third Bank, Cincinnati LOC), 0.400%, 6/1/2012 10,000,000
7,140,000 Sevier County, TN Public Building Authority, Local Government Public Improvement Bonds (Series VII-E-1) Weekly VRDNs (Oak Ridge, TN)/(KBC Bank N.V. LOC), 0.770%, 6/6/2012 7,140,000
TOTAL 17,140,000
Texas – 0.9%
4,095,000 3,4 Texas State Department of Housing & Community Affairs, P-FLOATs (Series PT-4594) Weekly VRDNs (Tranquility Housing Ltd.)/(GTD by FHLMC)/(FHLMC LIQ), 0.380%, 6/7/2012 4,095,000
Vermont – 2.6%
2,355,000 Vermont EDA, (Series 2008A) Weekly VRDNs (Green Mountain College)/(Key Bank, N.A. LOC), 0.260%, 6/7/2012 2,355,000
4,300,000 Vermont HFA, (Series A) Weekly VRDNs (Assured Guaranty Municipal Corp. INS)/(Bank of New York Mellon LIQ), 0.550%, 6/6/2012 4,300,000
5,500,000 Vermont HFA, (Series C) Weekly VRDNs (Assured Guaranty Municipal Corp. INS)/(Bank of New York Mellon LIQ), 0.550%, 6/6/2012 5,500,000
TOTAL 12,155,000
Virginia – 4.5%
4,000,000 Fairfax County, VA IDA, (Inova Health System), (Series 2010A-1), 0.300%, 6/7/2012 4,000,000
2,450,000 Halifax, VA IDA, MMMs, PCR (Series 1992), 1.25% CP (Virginia Electric & Power Co.), Mandatory Tender 6/12/2012 2,450,000
2,500,000 Hampton, VA IDA, (Series 1998) Weekly VRDNs (Waste Management, Inc.)/(Wells Fargo Bank, N.A. LOC), 0.230%, 6/7/2012 2,500,000
3,000,000 Hampton, VA Redevelopment & Housing Authority, (Series 1998) Weekly VRDNs (Township Apartments)/(FNMA LOC), 0.180%, 6/6/2012 3,000,000
2,000,000 Virginia Small Business Financing Authority, (Series 2010) Weekly VRDNs (Bon Secours Health System)/(JPMorgan Chase Bank, N.A. LOC), 0.170%, 6/6/2012 2,000,000
1,405,000 3,4 Virginia State Housing Development Authority, MERLOTS (Series 2006-B22) Weekly VRDNs (Wells Fargo Bank, N.A. LIQ), 0.250%, 6/6/2012 1,405,000
5,400,000 3,4 Virginia State, PUTTERs (Series 4195) Weekly VRDNs (JPMorgan Chase Bank, N.A. LIQ), 0.180%, 6/7/2012 5,400,000
TOTAL 20,755,000
Annual Shareholder Report
Principal
Amount		 Value
Wisconsin – 0.4%
$2,000,000 Combined Locks, WI IDRB, (Series 1997) Weekly VRDNs (Appleton Papers)/(Fifth Third Bank, Cincinnati LOC), 0.410%, 6/7/2012 2,000,000
TOTAL MUNICIPAL INVESTMENTS — 99.6%
(AT AMORTIZED COST)5 		459,630,658
OTHER ASSETS AND LIABILITIES - NET — 0.4%6 1,910,133
TOTAL NET ASSETS — 100% $461,540,791

Securities that are subject to the federal alternative minimum tax (AMT) represent 63.4% of the portfolio as calculated based upon total market value (percentage is unaudited).

1 The Fund may only invest in securities rated in one of the two highest short-term rating categories by nationally recognized statistical rating organizations (NRSROs) or unrated securities of comparable quality. An NRSRO's two highest rating categories are determined without regard for sub-categories and gradations. For example, securities rated SP-1+, SP-1 or SP-2 by Standard & Poor's, MIG-1 or MIG-2 by Moody's Investors Service or F-1+, F-1 or F-2 by Fitch Ratings, are all considered rated in one of the two highest short-term rating categories.
  Securities rated in the highest short-term rating category (and unrated securities of comparable quality) are identified as First Tier securities. Securities rated in the second highest short-term rating category (and unrated securities of comparable quality) are identified as Second Tier securities. The Fund follows applicable regulations in determining whether a security is rated and whether a security rated by multiple NRSROs in different rating categories should be identified as a First or Second Tier security.
  At May 31, 2012, the portfolio securities were rated as follows:
  Tier Rating Percentages Based on Total Market Value (unaudited)
First Tier Second Tier
97.1% 2.9%
2 Current rate and next reset date shown for Variable Rate Demand Notes.
3 Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At May 31, 2012, these restricted securities amounted to $106,091,000, which represented 23.0% of total net assets.
4 Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Directors (the “Directors”). At May 31, 2012, these liquid restricted securities amounted to $106,091,000, which represented 23.0% of total net assets.
5 Also represents cost for federal tax purposes.
6 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2012.

Annual Shareholder Report

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1 — quoted prices in active markets for identical securities, including investment companies with daily net asset values, if applicable.

Level 2 — other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3 — significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2012, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

AMT  — Alternative Minimum Tax
BANs  — Bond Anticipation Notes
COL  — Collateralized
CP  — Commercial Paper
CSD  — Central School District
EDA  — Economic Development Authority
EDRB  — Economic Development Revenue Bond
FHLB  — Federal Home Loan Bank
FHLMC  — Federal Home Loan Mortgage Corporation
FNMA  — Federal National Mortgage Association
GNMA  — Government National Mortgage Association
GTD  — Guaranteed
HFA  — Housing Finance Authority
IDA  — Industrial Development Authority
IDB  — Industrial Development Bond
IDFA  — Industrial Development Finance Authority
IDRB(s)  — Industrial Development Revenue Bond(s)
INS  — Insured
LIQ  — Liquidity Agreement
LOC  — Letter of Credit
MERLOTS  — Municipal Exempt Receipts-Liquidity Optional Tender Series
MFH  — Multi-Family Housing
MMMs  — Money Market Municipals
PCR  — Pollution Control Revenue
P-FLOATs  — Puttable Floating Option Tax-Exempt Receipts
PUTTERs  — Puttable Tax-Exempt Receipts
RANs  — Revenue Anticipation Notes
ROCs  — Reset Option Certificates
SPEARs  — Short Puttable Exempt Adjustable Receipts
TANs  — Tax Anticipation Notes
TOBs  — Tender Option Bonds
VRDNs  — Variable Rate Demand Notes
VRDPs  — Variable Rate Demand Preferreds

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31 2012 2011 2010 2009 2008
Net Asset Value, Beginning of Period $1.00 $1.00 $1.00 $1.00 $1.00
Income From Investment Operations:
Net investment income  —   —  0.0001 0.010 0.023
Net realized gain on investments 0.0001 0.0001 0.0001 0.0001 0.0001
TOTAL FROM INVESTMENT OPERATIONS 0.0001 0.0001 0.0001 0.010 0.023
Less Distributions:
Distributions from net investment income  —   —  (0.000)1 (0.010) (0.023)
Distributions from net realized gain on investments (0.000)1 (0.000)1  —  (0.000)1 (0.000)1
TOTAL DISTRIBUTIONS (0.000)1 (0.000)1 (0.000)1 (0.010) (0.023)
Net Asset Value, End of Period $1.00 $1.00 $1.00 $1.00 $1.00
Total Return2 0.00%3 0.00%3 0.03% 1.03% 2.36%
Ratios to Average Net Assets:
Net expenses 0.42% 0.49% 0.75% 1.08%4 1.05%4
Net investment income 0.00% 0.00% 0.03% 1.00% 2.26%
Expense waiver/reimbursement5 0.68% 0.59% 0.35% 0.05% 0.05%
Supplemental Data:
Net assets, end of period (000 omitted) $461,541 $539,081 $474,268 $512,018 $476,382
1 Represents less than $0.001.
2 Based on net asset value.
3 Represents less than 0.01%.
4 The net expense ratio is calculated without reduction for expense offset arrangements. The net expense ratios are 1.08% and 1.05% for the years ended May 31, 2009 and 2008, respectively, after taking into account these expense reductions.
5 This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Assets and Liabilities

May 31, 2012

Assets:
Total investment in securities, at amortized cost and fair value $459,630,658
Income receivable 670,658
Receivable for investments sold 1,410,000
TOTAL ASSETS 461,711,316
Liabilities:
Payable for shares redeemed $6,577
Bank overdraft 48,694
Payable for investment adviser fee (Note 5) 8,528
Payable for transfer and dividend disbursing agent fees and expenses 64,478
Payable for Directors'/Trustees' fees 660
Payable for portfolio accounting fees 8,250
Payable for share registration costs 27,561
Accrued expenses 5,777
TOTAL LIABILITIES 170,525
Net assets for 461,543,972 shares outstanding $461,540,791
Net Assets Consist of:
Paid-in capital $461,536,983
Accumulated net realized gain on investments 3,808
TOTAL NET ASSETS $461,540,791
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$461,540,791 ÷ 461,543,972 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized $1.00

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Operations

Year Ended May 31, 2012

Investment Income:
Interest $2,271,137
Expenses:
Investment adviser fee (Note 5) $2,706,504
Administrative fee (Note 5) 422,357
Custodian fees 21,352
Transfer and dividend disbursing agent fees and expenses 592,927
Directors'/Trustees' fees 6,725
Auditing fees 18,500
Legal fees 10,542
Portfolio accounting fees 95,313
Distribution services fee (Note 5) 541,301
Shareholder services fee (Note 5) 1,351,924
Account administration fee 1,108
Share registration costs 85,209
Printing and postage 27,684
Insurance premiums 4,803
Taxes 40,360
Miscellaneous 2,464
TOTAL EXPENSES 5,929,073
Waivers and Reimbursement (Note 5):
Waiver of investment adviser fee $(1,753,176)
Waiver of administrative fee (10,427)
Waiver of distribution services fee (541,301)
Waiver of shareholder services fee (1,351,924)
Waiver of account administration fee (965)
Reimbursement of account administration fee (143)
TOTAL WAIVERS AND REIMBURSEMENT (3,657,936)
Net expenses 2,271,137
Net investment income  — 
Net realized gain on investments 9,373
Change in net assets resulting from operations $9,373

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Changes in Net Assets

Year Ended May 31 2012 2011
Increase (Decrease) in Net Assets
Operations:
Net investment income $ —  $ — 
Net realized gain on investments 9,373 4,585
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS 9,373 4,585
Distributions to Shareholders:
Distributions from net realized gain on investments (5,565) (6,306)
Share Transactions:
Proceeds from sale of shares 1,332,559,828 1,403,633,028
Net asset value of shares issued to shareholders in payment of distributions declared 5,490 6,291
Cost of shares redeemed (1,410,109,704) (1,338,824,124)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS (77,544,386) 64,815,195
Change in net assets (77,540,578) 64,813,474
Net Assets:
Beginning of period 539,081,369 474,267,895
End of period $461,540,791 $539,081,369

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Notes to Financial Statements

May 31, 2012

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Municipal Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is to provide current income exempt from federal regular income tax consistent with stability of principal. Interest income from the Fund's investments may be subject to the federal AMT for individuals and corporations and state and local taxes.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate market value, the fair value of the portfolio securities will be determined under procedures established by and under the general supervision of the Directors.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective interest rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2012, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2012, tax years 2009 through 2012 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Annual Shareholder Report

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed Delivery Transactions

The Fund may engage in when-issued or delayed delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31 2012 2011
Shares sold 1,332,559,828 1,403,637,721
Shares issued to shareholders in payment of distributions declared 5,490 6,291
Shares redeemed (1,410,109,704) (1,338,824,124)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS (77,544,386) 64,819,888
Annual Shareholder Report

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2012 and 2011, was as follows:

2012 2011
Ordinary income1 $5,565 $ — 
Long-term capital gains $ —  $6,306
1 For tax purposes, short-term capital gains are treated as ordinary income distributions.

As of May 31, 2012, the components of distributable earnings on a tax basis were as follows:

Undistributed ordinary income2 $1,392
Undistributed long-term capital gains $2,416
2 For tax purposes, short-term capital gains are treated as ordinary income for distribution purposes.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

Federated Investment Management Company is the Fund's investment adviser (the “Adviser”). The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the Adviser voluntarily waived $1,753,176 of its fee.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. The fee paid to FAS is based on the average aggregate daily net assets of certain Federated funds as specified below:

Administrative Fee Average Aggregate Daily Net Assets
of the Federated Funds
0.150% on the first $5 billion
0.125% on the next $5 billion
0.100% on the next $10 billion
0.075% on assets in excess of $20 billion

The administrative fee received during any fiscal year shall be at least $150,000 per portfolio and $40,000 per each additional class of Shares. Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the net fee paid to FAS was 0.076% of average daily net assets of the Fund. FAS waived $10,427 of its fee.

Annual Shareholder Report

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, FSC voluntarily waived its entire fee of $541,301. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Shareholder Services Fee

The Fund may pay fees (“Service Fees”) up to 0.25% of the average daily net assets of the Fund's Shares to financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for Service Fees. For the year ended May 31, 2012, FSSC voluntarily reimbursed $143 of account administration fees. In addition, for the year ended May 31, 2012, unaffiliated third-party financial intermediaries waived $1,351,924 of shareholder services fees and $965 of account administration fees. These waivers can be modified or terminated at any time.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and its affiliates (which may include FSC, FAS and FSSC) have voluntarily agreed to waive their fees and/or reimburse expenses so that the total annual fund operating expenses (as shown in the financial highlights) paid by the Fund's Shares (after the voluntary waivers and reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2013; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing this arrangement prior to the Termination Date, this arrangement may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

Interfund Transactions

During the year ended May 31, 2012, the Fund engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees, and/or common Officers. These purchase and sale transactions complied with Rule 17a-7 under the Act and amounted to $1,054,190,000 and $1,241,430,000, respectively.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of the above companies.

Annual Shareholder Report

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the program was not utilized.

8. recent accounting pronouncements

In April 2011, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2011-03, “Reconsideration of Effective Control for Repurchase Agreements.” This ASU amends FASB Accounting Standards Codification (ASC) Topic 860, “Transfers and Servicing”; specifically the criteria required to determine whether a repurchase agreement and similar agreements should be accounted for as sales of financial assets or secured borrowings with commitments. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-03 is not expected to have a material impact on the Fund's financial statements and the accompanying notes, net assets or results of operations.

In addition, in May 2011, FASB released ASU No. 2011-04, “Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” This ASU amends FASB ASC Topic 820, “Fair Value Measurement,” to establish common requirements for measuring fair value and for disclosing information about fair value measurements in accordance with GAAP. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-04 is not expected to have a material impact on the Fund's financial statements and the accompanying notes.

Annual Shareholder Report

Report of Independent Registered Public Accounting Firm

TO THE BOARD OF DIRECTORS OF Cash trust Series, INc. AND SHAREHOLDERS Of Federated Municipal Cash series:

We have audited the accompanying statement of assets and liabilities of Federated Municipal Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2012, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2012, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Municipal Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2012, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 24, 2012

Annual Shareholder Report

Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or shareholder services fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2011 to May 31, 2012.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Annual Shareholder Report

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

Beginning
Account Value
12/1/2011 		Ending
Account Value
5/31/2012		 Expenses Paid
During Period1,2
Actual $1,000 $1,000.00 $2.00
Hypothetical (assuming a 5% return
before expenses)		 $1,000 $1,023.00 $2.02
1 Expenses are equal to the Fund's annualized net expense ratio of 0.40%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).
2 Actual and Hypothetical expenses paid during the period utilizing the Fund's current annualized net expense ratio of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect current expenses as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.
Annual Shareholder Report

Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2011, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 43 investment companies (comprising 134 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held and Previous Position(s)
John F. Donahue*
Birth Date: July 28, 1924
Director
Began serving: May 1989		 Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee.

Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.
J. Christopher Donahue*
Birth Date: April 11, 1949
President and Director
Began serving: May 1989		 Principal Occupations: Principal Executive Officer and President of the Federated Fund Family; Director or Trustee of some of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company.

Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.
Annual Shareholder Report

INDEPENDENT DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Nicholas P. Constantakis, CPA
Birth Date: September 3, 1939
Director
Began serving: February 1998		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorship Held: Director, Chairman of the Audit Committee, and member of the Compensation Committee, Michael Baker Corporation (architecture, engineering and construction services).

Previous Position: Partner, Andersen Worldwide SC.

Qualifications: Public accounting and director experience.
John F. Cunningham
Birth Date: March 5, 1943
Director
Began serving: January 1999		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorships Held: Chairman, President and Chief Executive Officer, Cunningham & Co., Inc. (strategic business consulting); Trustee Associate, Boston College.

Previous Positions: Director, Redgate Communications and EMC Corporation (computer storage systems); Chairman of the Board and Chief Executive Officer, Computer Consoles, Inc.; President and Chief Operating Officer, Wang Laboratories; Director, First National Bank of Boston; Director, Apollo Computer, Inc.

Qualifications: Business management and director experience.
Maureen Lally-Green
Birth Date: July 5, 1949
Director
Began serving: August 2009		 Principal Occupations: Director or Trustee of the Federated Fund Family; Director, Office of Church Relations, Diocese of Pittsburgh; Adjunct Professor of Law, Duquesne University School of Law.

Other Directorships Held: Director, Auberle; Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director, Ireland Institute of Pittsburgh; Chair and Director, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Saint Thomas More Society, Allegheny County.

Previous Position: Pennsylvania Superior Court Judge.

Qualifications: Legal and director experience.
Peter E. Madden
Birth Date: March 16, 1942
Director
Began serving: August 1991		 Principal Occupation: Director or Trustee, and Chairman of the Board of Directors or Trustees, of the Federated Fund Family.

Previous Positions: Representative, Commonwealth of Massachusetts General Court; President, Chief Operating Officer and Director, State Street Bank and Trust Company and State Street Corporation (retired); Director, VISA USA and VISA International; Chairman and Director, Massachusetts Bankers Association; Director, Depository Trust Corporation; Director, The Boston Stock Exchange.

Qualifications: Business management, mutual fund services and director experience.
Annual Shareholder Report
Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Charles F. Mansfield, Jr.
Birth Date: April 10, 1945
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant.

Previous Positions: Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President, DVC Group, Inc. (marketing, communications and technology).

Qualifications: Banking, business management, education and director experience.
Thomas M. O'Neill
Birth Date: June 14, 1951
Director
Began serving: October 2006		 Principal Occupations: Director or Trustee, Vice Chairman of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting).

Other Directorships Held: Board of Overseers, Children's Hospital of Boston; Visiting Committee on Athletics, Harvard College; Board of Directors, Medicines for Humanity; Board of Directors, The Golisano Children's Museum of Naples, Florida.

Previous Positions: Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); Director, Midway Pacific (lumber).

Qualifications: Business management, mutual fund, director and investment experience.
John S. Walsh
Birth Date: November 28, 1957
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee, Chairman of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc.

Previous Position: Vice President, Walsh & Kelly, Inc.

Qualifications: Business management and director experience.
Annual Shareholder Report

OFFICERS

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years
and Previous Position(s)
John W. McGonigle
Birth Date: October 26, 1938
EXECUTIVE VICE PRESIDENT AND SECRETARY
Began serving: May 1989		 Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc.

Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Richard A. Novak
Birth Date: December 25, 1963
Treasurer
Began serving: January 2006		 Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.

Previous Positions: Controller of Federated Investors, Inc.; Vice President, Finance of Federated Services Company; held various financial management positions within The Mercy Hospital of Pittsburgh; Auditor, Arthur Andersen & Co.
Richard B. Fisher
Birth Date: May 17, 1923
Vice Chairman
Began serving: August 2002		 Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp.

Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.
Brian P. Bouda
Birth Date: February 28, 1947
CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT
Began serving: August 2004		 Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin.
Deborah A. Cunningham
Birth Date: September 15, 1959
Chief Investment Officer
Began serving: May 2004		 Principal Occupations: Deborah A. Cunningham was named Chief Investment Officer of money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Mary Jo Ochson
Birth Date: September 12, 1953
Chief Investment Officer and Vice President
Began serving: November 1998		 Principal Occupations: Mary Jo Ochson has been the Fund's Portfolio Manager since August 1989. Ms. Ochson was named Chief Investment Officer of tax-exempt fixed-income products in 2004 and Chief Investment Officer of Tax-Free Money Markets in 2010 and is a Vice President of the Corporation. She joined Federated in 1982 and has been a Senior Portfolio Manager and a Senior Vice President of the Fund's Adviser since 1996. Ms. Ochson has received the Chartered Financial Analyst designation and holds an M.B.A. in Finance from the University of Pittsburgh.

Annual Shareholder Report

Evaluation and Approval of Advisory Contract – May 2012

FEDERATED MUNICIPAL CASH SERIES (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2012 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies exist, whether they have been shared with a fund and its shareholders; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent to which the Board members are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. Consistent with these judicial decisions, the Board also considered management fees (including any components thereof) charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

Annual Shareholder Report

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

Annual Shareholder Report

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant, given the high degree of competition in the mutual fund business. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a generally reliable indication of what consumers have found to be reasonable in the precise marketplace in which the Fund competes. In this regard, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes; different associated costs; different portfolio management techniques made necessary by different cash flows; and portfolio manager time spent in review of securities pricing. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory contracts.

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn assisted the Board in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups are relevant in judging the reasonableness of proposed fees.

The Fund's performance fell below the median of the relevant peer group for the one-year period covered by the Evaluation. The Board discussed the Fund's performance with the Adviser and recognized the efforts being undertaken by the Adviser. The Board will continue to monitor these efforts and the performance of the Fund.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The Annual Shareholder Report

information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution or elimination of these voluntary waivers.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, although they may apply consistent allocation processes, the inherent difficulties in allocating costs (and the unavoidable arbitrary aspects of that exercise) and the lack of consensus on how to allocate those costs may render such allocation information unreliable. The allocation information was considered in the analysis by the Board but was determined to be of limited use.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer noted the limited availability of such information, but nonetheless concluded that Federated's profit margins did not appear to be excessive.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies, should they exist) were likely to be enjoyed by the fund complex as a whole. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size. The Senior Officer did not recommend institution of breakpoints in pricing Federated's fund advisory services at this time.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee, after waivers and expense reimbursements, if any, was above the median of the relevant peer group. The Board reviewed the fees and other expenses of the Fund with the Adviser and was satisfied that the overall expense structure of the Fund remained competitive. The Board will continue to monitor advisory fees and other expenses borne by the Fund.
Annual Shareholder Report

The Senior Officer noted that, considering the totality of the circumstances, and all of the factors referenced within his Evaluation, he had concluded that, subject to comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds was reasonable and that Federated appeared to provide appropriate advisory and administrative services to the Fund for the fees paid. Under these circumstances, no changes were recommended to, and no objection was raised to, the continuation of the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

Annual Shareholder Report

Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available from Federated's website at FederatedInvestors.com. To access this information from the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Proxy Voting Record Report (Form N-PX).” Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information from the “Products” section of Federated's website at FederatedInvestors.com. From the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Form N-Q.”

Annual Shareholder Report

Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Municipal Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551303



28565 (7/12)

Federated is a registered trademark of Federated Investors, Inc.
2012  © Federated Investors, Inc.

Annual Shareholder Report

May 31, 2012


Ticker CTPXX

Not FDIC Insured

May Lose Value

No Bank Guarantee


Federated Prime Cash Series

A Portfolio of Cash Trust Series, Inc.

CONTENTS

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2012, the Fund's portfolio composition1 was as follows:

Security Type Percentage of
Total Net Assets
Commercial Paper and Notes 49.5%
Bank Instruments 24.3%
Variable Rate Instruments 19.1%
Repurchase Agreements 6.1%
U.S. Treasury Securities 1.0%
Other Assets and Liabilities — Net2,3 0.0%
TOTAL 100.0%

At May 31, 2012, the Fund's effective maturity schedule4 was as follows:

Securities with an
Effective Maturity of:		 Percentage of
Total Net Assets
1-7 Days 32.8%
8-30 Days 29.5%
31-90 Days 28.6%
91-180 Days 5.9%
181 Days or more 3.2%
Other Assets and Liabilities — Net2,3 0.0%
TOTAL 100.0%
1 See the Fund's Prospectus and Statement of Additional Information for more complete information regarding these security types. With respect to this table, Commercial Paper and Notes includes asset-backed securities, collateralized loan agreements, commercial paper, corporate bonds and loan participation, with interest rates that are fixed or that reset periodically.
2 Represents less than 0.1%.
3 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
4 Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.
Annual Shareholder Report

Portfolio of Investments

May 31, 2012

Principal
Amount		 Value
Asset-Backed Securities – 3.4%
Finance - Automotive – 1.4%
$10,949,815 Ally Auto Receivables Trust 2012-2, Class A1, 0.314%, 3/15/2013 10,949,815
13,734,359 AmeriCredit Automobile Receivables Trust 2012-2, Class A1, 0.300%, 5/8/2013 13,734,359
1,871,306 Honda Auto Receivables Owner Trust 2011-3, Class A1, 0.398%, 10/22/2012 1,871,306
14,613,602 Nissan Auto Lease Trust 2012-A, Class A1, 0.344%, 3/15/2013 14,613,602
TOTAL 41,169,082
Finance - Equipment – 0.5%
484,778 GE Equipment Mid Ticket LLC, (Series 2011-1), Class A1, 0.429%, 10/22/2012 484,778
3,000,000 1,2 GE Equipment Small Ticket LLC (Series 2012-1), Class A1, 0.433%, 6/21/2013 3,000,000
7,741,040 GE Equipment Transportation LLC, (Series 2012-1), Class A1, 0.389%, 3/22/2013 7,741,040
3,941,584 1,2 Great America Leasing Receivables 2012-1, Class A1, 0.520%, 4/15/2013 3,941,584
TOTAL 15,167,402
Finance - Retail – 1.5%
10,000,000 1,2,3 Arkle Master Issuer PLC 2012-1, Class 1A, 0.440%, 6/17/2012 10,000,000
25,000,000 1,2,3 Holmes Master Issuer PLC 2011-3, Class A1, 0.369%, 6/15/2012 25,000,000
11,000,000 1,2,3 Holmes Master Issuer PLC 2012-1, Class A1, 0.439%, 6/15/2012 11,000,000
TOTAL 46,000,000
TOTAL ASSET-BACKED SECURITIES 102,336,484
Certificates of Deposit – 24.3%
Finance - Banking – 24.3%
40,000,000 3 Bank of Montreal, 0.389%, 6/14/2012 40,000,000
25,000,000 3 Bank of Montreal, 0.429%, 6/29/2012 25,000,000
145,000,000 Bank of Tokyo-Mitsubishi UFJ Ltd., 0.360% - 0.370%,
6/1/2012 - 8/15/2012		 145,000,000
5,000,000 Barclays Bank PLC, 0.400%, 6/6/2012 5,000,000
25,000,000 Credit Suisse, Zurich, 0.300%, 7/5/2012 25,000,000
25,000,000 3 Credit Suisse, Zurich, 0.369%, 6/8/2012 25,000,000
110,000,000 Deutsche Bank AG, 0.440%, 8/17/2012 - 8/22/2012 110,000,000
25,000,000 3 Deutsche Bank AG, 0.717%, 8/21/2012 25,000,000
110,000,000 Mizuho Corporate Bank Ltd., 0.330% - 0.350%, 8/1/2012 - 8/27/2012 110,000,000
40,000,000 Natixis, 0.320%, 6/7/2012 40,000,000
Annual Shareholder Report
Principal
Amount		 Value
$35,000,000 3 Rabobank Nederland NV, Utrecht, 0.389%, 6/13/2012 35,000,000
25,000,000 3 Royal Bank of Canada, Montreal, 0.536%, 8/6/2012 25,000,000
25,000,000 3 Royal Bank of Canada, Montreal, 0.544%, 6/18/2012 25,000,000
20,000,000 3 Royal Bank of Canada, Montreal, 0.544%, 6/21/2012 20,000,000
50,000,000 3 Toronto Dominion Bank, 0.439%, 6/11/2012 50,000,000
15,000,000 3 Westpac Banking Corp. Ltd., Sydney, 0.339%, 6/18/2012 15,000,000
TOTAL CERTIFICATES OF DEPOSIT 720,000,000
Collateralized Loan Agreements – 9.8%
Finance - Banking – 9.8%
25,000,000 Citigroup Global Markets, Inc., 0.679%, 6/1/2012 25,000,000
15,000,000 Credit Suisse Securities (USA) LLC, 0.882%, 7/25/2012 15,000,000
50,000,000 Goldman Sachs & Co., 0.466%, 6/5/2012 50,000,000
85,000,000 Merrill Lynch, Pierce, Fenner & Smith, Inc., 0.477% - 0.770%,
6/1/2012 - 8/21/2012		 85,000,000
35,000,000 Mizuho Securities USA, Inc., 0.375%, 6/1/2012 35,000,000
20,000,000 RBC Capital Markets, LLC, 0.542%, 7/24/2012 20,000,000
60,000,000 RBS Securities, Inc., 0.568%, 6/6/2012 60,000,000
TOTAL COLLATERALIZED LOAN AGREEMENTS 290,000,000
Commercial Paper – 33.4%4
Aerospace/Auto – 0.5%
6,400,000 1,2 Daimler Finance NA LLC, (GTD by Daimler AG), 0.400% - 0.410%, 6/15/2012 - 6/18/2012 6,398,780
8,800,000 1,2 Nissan Motor Acceptance Corp., (Nissan Motor Co., Ltd. Support Agreement), 0.430% - 0.440%, 6/11/2012 8,798,930
TOTAL 15,197,710
Consumer Products – 0.1%
2,200,000 Clorox Co., 0.400%, 6/5/2012 2,199,902
Electric Power – 0.0%
500,000 1,2 Eaton Corp., 0.430%, 6/12/2012 499,934
Finance - Banking – 21.7%
70,000,000 1,2 Australia & New Zealand Banking Group, Melbourne, 0.356% - 0.602%, 6/15/2012 - 11/27/2012 69,953,031
110,000,000 Citigroup Funding, Inc., (GTD by Citigroup, Inc.), 0.550% - 0.581%, 6/8/2012 - 7/6/2012 109,979,155
25,000,000 1,2 Commonwealth Bank of Australia, 0.602%, 6/7/2012 24,997,500
85,000,000 Credit Agricole North America, Inc., 0.395% - 0.400%,
6/6/2012 - 6/25/2012		 84,979,451
100,000,000 ING (U.S.) Funding LLC, 0.350% - 0.420%, 7/3/2012 - 8/15/2012 99,938,024
Annual Shareholder Report
Principal
Amount		 Value
$105,000,000 1,2 National Australia Funding (Delaware), Inc., 0.351% - 0.371%, 8/17/2012 - 11/21/2012 104,856,830
35,000,000 Societe Generale North America, Inc., (GTD by Societe Generale, Paris), 0.420%, 6/4/2012 34,998,775
40,000,000 1,2 Surrey Funding Corporation, 0.300%, 8/7/2012 39,977,667
75,000,000 Westpac Banking Corp. Ltd., Sydney, 0.401%, 8/6/2012 74,945,000
TOTAL 644,625,433
Finance - Commercial – 2.9%
40,000,000 General Electric Capital Corp., 0.351%, 10/4/2012 39,951,389
20,000,000 1,2 Starbird Funding Corp., 0.430%, 6/25/2012 19,994,267
25,000,000 1,2 Versailles Commercial Paper LLC, 0.480%, 6/18/2012 24,994,333
TOTAL 84,939,989
Finance - Retail – 3.5%
25,000,000 1,2 Barton Capital LLC, 0.300%, 6/6/2012 24,998,958
40,000,000 1,2 Sheffield Receivables Corp., 0.340%, 6/1/2012 40,000,000
40,000,000 1,2 Windmill Funding Corp., 0.300%, 6/15/2012 39,995,334
TOTAL 104,994,292
Machinery/Equipment/Auto – 0.2%
4,700,000 1,2 Harley-Davidson Funding Corp., (Harley-Davidson, Inc. Support Agreement), 0.410% - 0.420%, 6/1/2012 - 6/12/2012 4,699,615
Oil & Oil Finance – 0.3%
7,500,000 1,2 Devon Energy Corp., 0.440%, 6/1/2012 7,500,000
Sovereign – 3.9%
115,000,000 1,2 Caisse des Depots et Consignations (CDC), 0.340% - 0.400%, 7/18/2012 - 8/15/2012 114,934,361
Telecommunications – 0.3%
10,000,000 1,2 Comcast Corp., 0.400%, 6/21/2012 - 6/22/2012 9,997,761
TOTAL COMMERCIAL PAPER 989,588,997
Corporate Bonds – 1.6%
Diversified – 0.0%
1,000,000 General Electric Co., 5.000%, 2/1/2013 1,027,108
Finance - Commercial – 1.6%
1,938,000 3 General Electric Capital Corp., 0.616%, 8/8/2012 1,939,254
500,000 General Electric Capital Corp., 2.800%, 1/8/2013 506,723
22,331,000 General Electric Capital Corp., 5.250%, 10/19/2012 22,717,663
5,920,000 General Electric Capital Corp., 5.450%, 1/15/2013 6,099,352
Annual Shareholder Report
Principal
Amount		 Value
$15,488,000 General Electric Capital Corp., 6.000%, 6/15/2012 15,520,034
TOTAL 46,783,026
TOTAL CORPORATE BONDS 47,810,134
Loan Participation – 1.3%
Chemicals – 1.3%
38,000,000 DuPont Teijin Films U.K. Ltd., (GTD by Du Pont (E.I.) de Nemours & Co.), 0.400%, 6/28/2012 38,000,000
Notes — Variable – 19.1%3
Finance - Banking – 16.6%
1,580,000 6380 Brackbill Associates LP, (Series 2000), (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.590%, 6/1/2012 1,580,000
43,585,000 Albany-Dougherty County, GA Hospital Authority, (Series 2008A), (SunTrust Bank LOC), 0.360%, 6/1/2012 43,585,000
50,000,000 Australia & New Zealand Banking Group, Melbourne, 0.414%, 6/6/2012 50,000,000
20,000,000 Australia & New Zealand Banking Group, Melbourne, 0.475%, 6/7/2012 20,000,000
2,000,000 1,2 BlackRock Municipal Bond Trust, VMTP Preferred Shares (Series T0014), 0.330%, 6/1/2012 2,000,000
15,000,000 Carew Realty, Inc., (Series 2012), (Fifth Third Bank, Cincinnati LOC), 0.330%, 6/1/2012 15,000,000
10,830,000 1,2 Chicago, IL, SPEARs (Series DB-494), 0.240%, 6/7/2012 10,830,000
20,000,000 Commonwealth Bank of Australia, 0.495%, 6/1/2012 20,000,000
3,545,000 Gannett Fleming, Inc., (Series 2001), (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.590%, 6/1/2012 3,545,000
1,590,000 Graywood Farms LLC, (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.590%, 6/1/2012 1,590,000
46,035,000 1,2 Illinois State, Taxable PUTTERs (Series SGT01), 0.450%, 6/1/2012 46,035,000
47,000,000 JPMorgan Chase Bank, N.A., 0.359%, 6/28/2012 47,000,000
93,000,000 JPMorgan Chase Bank, N.A., 0.360%, 6/21/2012 93,000,000
4,550,000 MOBR-04 LLC, (Series 2004), (Compass Bank, Birmingham LOC), 1.850%, 6/7/2012 4,550,000
50,000,000 Maryland State Economic Development Corp., (Series 2001A) Human Genome Sciences, (Manufacturers & Traders Trust Co., Buffalo, NY LOC), 0.590%, 6/5/2012 50,000,000
7,770,000 New York City Housing Development Corp., (Series 2009-A1), (RBS Citizens Bank N.A. LOC), 0.200%, 6/6/2012 7,770,000
6,995,000 New York City Housing Development Corp., (Series 2010-A2), (RBS Citizens Bank N.A. LOC), 0.200%, 6/6/2012 6,995,000
16,140,000 Serra Works Bond Holding Co. LLC, (Series 2008-A), (Fifth Third Bank, Cincinnati LOC), 0.300%, 6/7/2012 16,140,000
Annual Shareholder Report
Principal
Amount		 Value
$1,100,000 South Pittsburg, TN IDB, Lodge Manufacturing Co. Project, (Series 1999), (SunTrust Bank LOC), 0.600%, 6/6/2012 1,100,000
3,255,000 Sun Valley, Inc., (Wells Fargo Bank, N.A. LOC), 0.260%, 6/1/2012 3,255,000
20,000,000 1,2 Svenska Handelsbanken, Stockholm, 0.516%, 8/17/2012 20,000,000
14,595,000 Texas State, Veterans' Housing Assistance Program, Fund II (Series 2004B), 0.190%, 6/6/2012 14,595,000
9,800,000 Village Green Finance Co. LLC, (Series 1997), (Wells Fargo Bank, N.A. LOC), 0.210%, 6/6/2012 9,800,000
3,505,000 Wiley Properties, Inc., (Series 2002), (Fifth Third Bank, Cincinnati LOC), 0.330%, 6/7/2012 3,505,000
TOTAL 491,875,000
Finance - Commercial – 0.5%
1,900,000 1,2 KORDSA, Inc., (Series 2006), (General Electric Capital Corp. LOC), 0.260%, 6/7/2012 1,900,000
13,205,000 1,2 Mountain Creek Properties LLC, (General Electric Capital Corp. LOC), 0.260%, 6/7/2012 13,205,000
TOTAL 15,105,000
Finance - Retail – 1.1%
32,000,000 AFS Insurance Premium Receivables Trust, (Series 1994-A), 0.794%, 6/15/2012 32,000,000
Government Agency – 0.9%
18,155,000 BBC Enterprises LLC, (Series 2007), (FHLB of San Francisco LOC), 0.150%, 6/7/2012 18,155,000
10,000,000 Capital Trust Agency, FL, (FNMA LOC), 0.210%, 6/7/2012 10,000,000
TOTAL 28,155,000
TOTAL NOTES — VARIABLE 567,135,000
U.S. Treasury Note – 1.0%
U.S. Treasury Note – 1.0%
29,000,000 United States Treasury, 3.125%, 4/30/2013 29,761,207
Repurchase Agreements – 6.1%
31,171,000 Interest in $4,190,000,000 joint repurchase agreement 0.21%, dated 5/31/2012 under which Bank of America, N.A. will repurchase securities provided as collateral for $4,190,024,442 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 7/25/2041 and the market value of those underlying securities was $4,299,453,202. 31,171,000
Annual Shareholder Report
Principal
Amount		 Value
$150,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.21%, dated 5/31/2012 under which Mizuho Securities USA, Inc. will repurchase securities provided as collateral for $1,000,005,833 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Government Agency securities with various maturities to 2/15/2042 and the market value of those underlying securities was $1,025,569,568. 150,000,000
TOTAL REPURCHASE AGREEMENTS 181,171,000
TOTAL INVESTMENTS — 100.0%
(AT AMORTIZED COST)5 		2,965,802,822
OTHER ASSETS AND LIABILITIES - NET — 0.0%6 965,119
TOTAL NET ASSETS — 100% $2,966,767,941
1 Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At May 31, 2012, these restricted securities amounted to $689,508,885, which represented 23.2% of total net assets.
2 Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Directors (the “Directors”). At May 31, 2012, these liquid restricted securities amounted to $689,508,885, which represented 23.2% of total net assets.
3 Denotes a variable rate security with current rate and next reset date shown.
4 Discount rate at time of purchase.
5 Also represents cost for federal tax purposes.
6 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2012.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1 — quoted prices in active markets for identical securities, including investment companies with daily net asset values, if applicable.

Level 2 — other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3 — significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

Annual Shareholder Report

As of May 31, 2012, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

FHLB  — Federal Home Loan Bank
FNMA  — Federal National Mortgage Association
GTD  — Guaranteed
IDB  — Industrial Development Bond
LOC  — Letter of Credit
PUTTERs  — Puttable Tax-Exempt Receipts
SPEARs  — Short Puttable Exempt Adjustable Receipts

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31 2012 2011 2010 2009 2008
Net Asset Value, Beginning of Period $1.00 $1.00 $1.00 $1.00 $1.00
Income From Investment Operations:
Net investment income 0.0001 0.0001 0.0001 0.014 0.036
Net realized gain on investments (0.000)1 0.0001 0.0001  —   — 
TOTAL FROM INVESTMENT OPERATIONS 0.0001 0.0001 0.0001 0.014 0.036
Less Distributions:
Distributions from net investment income (0.000)1 (0.000)1 (0.000)1 (0.014) (0.036)
Distributions from net realized gain on investments (0.000)1 (0.000)1 (0.000)1  —   — 
TOTAL DISTRIBUTIONS (0.000)1 (0.000)1 (0.000)1 (0.014) (0.036)
Net Asset Value, End of Period $1.00 $1.00 $1.00 $1.00 $1.00
Total Return2 0.01% 0.01% 0.01% 1.39% 3.70%
Ratios to Average Net Assets:
Net expenses 0.38% 0.43% 0.58% 1.08% 1.05%
Net investment income 0.01% 0.01% 0.01% 1.34% 3.58%
Expense waiver/reimbursement3 0.70% 0.65% 0.49% 0.01% 0.02%
Supplemental Data:
Net assets, end of period (000 omitted) $2,966,768 $4,559,876 $4,791,221 $6,661,244 $5,787,122
1 Represents less than $0.001.
2 Based on net asset value.
3 This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Assets and Liabilities

May 31, 2012

Assets:
Total investment in securities, at amortized cost and fair value $2,965,802,822
Cash 306,814
Income receivable 1,350,823
Receivable for shares sold 309,085
TOTAL ASSETS 2,967,769,544
Liabilities:
Payable for shares redeemed $396,053
Income distribution payable 82
Payable for investment adviser fee (Note 5) 126,552
Payable for transfer and dividend disbursing agent fees and expenses 388,422
Payable for Directors'/Trustees' fees 8,172
Payable for share registration costs 52,543
Accrued expenses 29,779
TOTAL LIABILITIES 1,001,603
Net assets for 2,966,780,122 shares outstanding $2,966,767,941
Net Assets Consist of:
Paid-in capital $2,966,780,122
Accumulated net realized loss on investments (12,099)
Distributions in excess of net investment income (82)
TOTAL NET ASSETS $2,966,767,941
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$2,966,767,941 ÷ 2,966,780,122 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized $1.00

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Operations

Year Ended May 31, 2012

Investment Income:
Interest $13,678,001
Expenses:
Investment adviser fee (Note 5) $17,674,367
Administrative fee (Note 5) 2,758,355
Custodian fees 143,455
Transfer and dividend disbursing agent fees and expenses 3,871,270
Directors'/Trustees' fees 37,241
Auditing fees 20,875
Legal fees 9,734
Portfolio accounting fees 161,460
Distribution services fee (Note 5) 3,534,873
Shareholder services fee (Note 5) 8,835,866
Share registration costs 248,482
Printing and postage 339,887
Insurance premiums 10,256
Taxes 290,925
Miscellaneous 15,706
TOTAL EXPENSES 37,952,752
Waivers and Reimbursement (Note 5):
Waiver of investment adviser fee $(12,186,085)
Waiver of administrative fee (68,316)
Waiver of distribution services fee (3,534,873)
Waiver of shareholder services fee (8,833,470)
Reimbursement of shareholder services fee (2,396)
TOTAL WAIVERS AND REIMBURSEMENT (24,625,140)
Net expenses 13,327,612
Net investment income 350,389
Net realized loss on investments (9,749)
Change in net assets resulting from operations $340,640

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Changes in Net Assets

Year Ended May 31 2012 2011
Increase (Decrease) in Net Assets
Operations:
Net investment income $350,389 $469,270
Net realized gain (loss) on investments (9,749) 5,207
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS 340,640 474,477
Distributions to Shareholders:
Distributions from net investment income (350,664) (469,522)
Distributions from net realized gain on investments (6,502) (4,832)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS (357,166) (474,354)
Share Transactions:
Proceeds from sale of shares 4,885,313,197 7,226,461,421
Net asset value of shares issued to shareholders in payment of distributions declared 354,685 472,738
Cost of shares redeemed (6,478,759,153) (7,458,279,390)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS (1,593,091,271) (231,345,231)
Change in net assets (1,593,107,797) (231,345,108)
Net Assets:
Beginning of period 4,559,875,738 4,791,220,846
End of period (including undistributed (distributions in excess of) net investment income of $(82) and $193, respectively) $2,966,767,941 $4,559,875,738

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Notes to Financial Statements

May 31, 2012

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as a diversified open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Prime Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate market value, the fair value of the portfolio securities will be determined under procedures established by and under the general supervision of the Directors.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

Annual Shareholder Report

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective interest rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2012, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2012, tax years 2009 through 2012 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed Delivery Transactions

The Fund may engage in when-issued or delayed delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the Annual Shareholder Report

securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated.

3. capital stock

The following table summarizes capital stock activity:

Year Ended May 31 2012 2011
Shares sold 4,885,313,197 7,226,461,421
Shares issued to shareholders in payment of distributions declared 354,685 472,738
Shares redeemed (6,478,759,153) (7,458,279,390)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS (1,593,091,271) (231,345,231)

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2012 and 2011, was as follows:

2012 2011
Ordinary income1 $357,166 $474,354
1 For tax purposes, short-term capital gain distributions are treated as ordinary income distributions.

As of May 31, 2012, the components of distributable earnings on a tax basis were as follows:

Distributions in excess of ordinary income $(82)
Capital loss deferrals $(12,099)

Under current tax regulations, capital losses on securities transactions realized after October 31 may be deferred and treated as occurring on the first day of the following fiscal year. As of the year ended May 31, 2012, for federal income tax purposes, post October losses of $12,099 were deferred to June 1, 2012.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

Federated Investment Management Company is the Fund's investment adviser (the “Adviser”). The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the Adviser voluntarily waived $12,186,085 of its fee.

Annual Shareholder Report

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. The fee paid to FAS is based on the average aggregate daily net assets of certain Federated funds as specified below:

Administrative Fee Average Aggregate Daily Net Assets
of the Federated Funds
0.150% on the first $5 billion
0.125% on the next $5 billion
0.100% on the next $10 billion
0.075% on assets in excess of $20 billion

The administrative fee received during any fiscal year shall be at least $150,000 per portfolio and $40,000 per each additional class of Shares. Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the net fee paid to FAS was 0.076% of average daily net assets of the Fund. FAS waived $68,316 of its fee.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, FSC voluntarily waived its entire fee of $3,534,873. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Shareholder Services Fee

The Fund may pay fees (“Service Fees”) up to 0.25% of the average daily net assets of the Fund's Shares to financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for Service Fees. For the year ended May 31, 2012, FSSC voluntarily reimbursed $2,396 of Service Fees. In addition, for the year ended May 31, 2012, unaffiliated third-party financial intermediaries waived $8,833,470 of Service Fees. This waiver can be modified or terminated at any time.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and its affiliates (which may include FSC, FAS and FSSC) have voluntarily agreed to waive their fees and/or reimburse expenses so that the total annual fund operating expenses (as shown in the financial highlights) paid by the Fund (after the voluntary waivers and reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Annual Shareholder Report

Date”): (a) August 1, 2013; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

Interfund Transactions

During the year ended May 31, 2012, the Fund engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees and/or common Officers. These purchase and sale transactions complied with Rule 17a-7 under the Act and amounted to $15,380,000 and $163,025,000, respectively.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of the above companies.

6. CONCENTRATION OF RISK

A substantial part of the Fund's portfolio may be comprised of obligations of banks. As a result, the Fund may be more susceptible to any economic, business, political or other developments which generally affect these entities.

7. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the Fund did not utilize the LOC.

8. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the program was not utilized.

Annual Shareholder Report

9. RECENT ACCOUNTING PRONOUNCEMENTS

In April 2011, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2011-03, “Reconsideration of Effective Control for Repurchase Agreements.” This ASU amends FASB Accounting Standards Codification (ASC) Topic 860, “Transfers and Servicing”; specifically the criteria required to determine whether a repurchase agreement and similar agreements should be accounted for as sales of financial assets or secured borrowings with commitments. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-03 is not expected to have a material impact on the Fund's financial statements and the accompanying notes, net assets or results of operations.

In addition, in May 2011, FASB released ASU No. 2011-04, “Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” This ASU amends FASB ASC Topic 820, “Fair Value Measurement,” to establish common requirements for measuring fair value and for disclosing information about fair value measurements in accordance with GAAP. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-04 is not expected to have a material impact on the Fund's financial statements and the accompanying notes.

Annual Shareholder Report

Report of Independent Registered Public Accounting Firm

TO THE BOARD OF TRUSTEES OF Cash trust Series, INc. AND SHAREHOLDERS Of Federated Prime Cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Prime Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2012, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2012, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Prime Cash Series, a portfolio of Cash Trust Series, Inc., at May 31, 2012, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 24, 2012

Annual Shareholder Report

Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or shareholder services fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2011 to May 31, 2012.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Annual Shareholder Report

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

Beginning
Account Value
12/1/2011		 Ending
Account Value
5/31/2012		 Expenses Paid
During Period1,2
Actual $1,000 $1,000.10 $2.10
Hypothetical (assuming a 5% return
before expenses)		 $1,000 $1,022.90 $2.12
1 Expenses are equal to the Fund's annualized net expense ratio of 0.42%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).
2 Actual and Hypothetical expenses paid during the period utilizing the Fund's current annualized net expense ratio of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect current expenses as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.
Annual Shareholder Report

Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2011, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 43 investment companies (comprising 134 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held and Previous Position(s)
John F. Donahue*
Birth Date: July 28, 1924
Director
Began serving: May 1989		 Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee.

Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.
J. Christopher Donahue*
Birth Date: April 11, 1949
President and Director
Began serving: May 1989		 Principal Occupations: Principal Executive Officer and President of the Federated Fund Family; Director or Trustee of some of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company.

Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.
Annual Shareholder Report

INDEPENDENT DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Nicholas P. Constantakis, CPA
Birth Date: September 3, 1939
Director
Began serving: February 1998		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorship Held: Director, Chairman of the Audit Committee, and member of the Compensation Committee, Michael Baker Corporation (architecture, engineering and construction services).

Previous Position: Partner, Andersen Worldwide SC.

Qualifications: Public accounting and director experience.
John F. Cunningham
Birth Date: March 5, 1943
Director
Began serving: January 1999		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorships Held: Chairman, President and Chief Executive Officer, Cunningham & Co., Inc. (strategic business consulting); Trustee Associate, Boston College.

Previous Positions: Director, Redgate Communications and EMC Corporation (computer storage systems); Chairman of the Board and Chief Executive Officer, Computer Consoles, Inc.; President and Chief Operating Officer, Wang Laboratories; Director, First National Bank of Boston; Director, Apollo Computer, Inc.

Qualifications: Business management and director experience.
Maureen Lally-Green
Birth Date: July 5, 1949
Director
Began serving: August 2009		 Principal Occupations: Director or Trustee of the Federated Fund Family; Director, Office of Church Relations, Diocese of Pittsburgh; Adjunct Professor of Law, Duquesne University School of Law.

Other Directorships Held: Director, Auberle; Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director, Ireland Institute of Pittsburgh; Chair and Director, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Saint Thomas More Society, Allegheny County.

Previous Position: Pennsylvania Superior Court Judge.

Qualifications: Legal and director experience.
Peter E. Madden
Birth Date: March 16, 1942
Director
Began serving: August 1991		 Principal Occupation: Director or Trustee, and Chairman of the Board of Directors or Trustees, of the Federated Fund Family.

Previous Positions: Representative, Commonwealth of Massachusetts General Court; President, Chief Operating Officer and Director, State Street Bank and Trust Company and State Street Corporation (retired); Director, VISA USA and VISA International; Chairman and Director, Massachusetts Bankers Association; Director, Depository Trust Corporation; Director, The Boston Stock Exchange.

Qualifications: Business management, mutual fund services and director experience.
Annual Shareholder Report
Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Charles F. Mansfield, Jr.
Birth Date: April 10, 1945
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant.

Previous Positions: Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President, DVC Group, Inc. (marketing, communications and technology).

Qualifications: Banking, business management, education and director experience.
Thomas M. O'Neill
Birth Date: June 14, 1951
Director
Began serving: October 2006		 Principal Occupations: Director or Trustee, Vice Chairman of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting).

Other Directorships Held: Board of Overseers, Children's Hospital of Boston; Visiting Committee on Athletics, Harvard College; Board of Directors, Medicines for Humanity; Board of Directors, The Golisano Children's Museum of Naples, Florida.

Previous Positions: Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); Director, Midway Pacific (lumber).

Qualifications: Business management, mutual fund, director and investment experience.
John S. Walsh
Birth Date: November 28, 1957
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee, Chairman of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc.

Previous Position: Vice President, Walsh & Kelly, Inc.

Qualifications: Business management and director experience.
Annual Shareholder Report

OFFICERS

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years
and Previous Position(s)
John W. McGonigle
Birth Date: October 26, 1938
EXECUTIVE VICE PRESIDENT AND SECRETARY
Began serving: May 1989		 Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc.

Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Richard A. Novak
Birth Date: December 25, 1963
Treasurer
Began serving: January 2006		 Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.

Previous Positions: Controller of Federated Investors, Inc.; Vice President, Finance of Federated Services Company; held various financial management positions within The Mercy Hospital of Pittsburgh; Auditor, Arthur Andersen & Co.
Richard B. Fisher
Birth Date: May 17, 1923
Vice Chairman
Began serving: August 2002		 Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp.

Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.
Brian P. Bouda
Birth Date: February 28, 1947
CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT
Began serving: August 2004		 Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin.
Deborah A. Cunningham
Birth Date: September 15, 1959
CHIEF INVESTMENT OFFICER
Began serving: May 2004		 Principal Occupations: Deborah A. Cunningham was named Chief Investment Officer of money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Paige M. Wilhelm
Birth Date: May 28, 1962
Vice President
Began serving: June 2012		 Principal Occupations: Paige M. Wilhelm has been the Fund's Portfolio Manager since April 1997. She is Vice President of the Fund. Ms. Wilhelm joined Federated in 1985 and has been a Sr. Vice President of the Funds Adviser since January 2006 and a Senior Portfolio Manager since January 2004. She is responsible for portfolio management and research in the fixed-income area concentrating on taxable money market instruments. Previous associations include Senior Credit Analyst, Federated Investors; Performance Analysis Supervisor; Performance Analyst, Federated Investment Counseling. Ms. Wilhelm is a member of the CFA Society of Pittsburgh and received her B.S. from Indiana University and her M.B.A. from Duquesne University.

Annual Shareholder Report

Evaluation and Approval of Advisory Contract – May 2012

FEDERATED PRIME CASH SERIES (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2012 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies exist, whether they have been shared with a fund and its shareholders; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent to which the Board members are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. Consistent with these judicial decisions, the Board also considered management fees (including any components thereof) charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

Annual Shareholder Report

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

Annual Shareholder Report

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant, given the high degree of competition in the mutual fund business. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a generally reliable indication of what consumers have found to be reasonable in the precise marketplace in which the Fund competes. In this regard, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes; different associated costs; different portfolio management techniques made necessary by different cash flows; and portfolio manager time spent in review of securities pricing. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory contracts.

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn assisted the Board in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups are relevant in judging the reasonableness of proposed fees.

For the one-year period covered by the Evaluation, the Fund's performance was above the median of the relevant peer group.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be Annual Shareholder Report

competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution or elimination of these voluntary waivers.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, although they may apply consistent allocation processes, the inherent difficulties in allocating costs (and the unavoidable arbitrary aspects of that exercise) and the lack of consensus on how to allocate those costs may render such allocation information unreliable. The allocation information was considered in the analysis by the Board but was determined to be of limited use.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer noted the limited availability of such information, but nonetheless concluded that Federated's profit margins did not appear to be excessive.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies, should they exist) were likely to be enjoyed by the fund complex as a whole. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size. The Senior Officer did not recommend institution of breakpoints in pricing Federated's fund advisory services at this time.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee, after waivers and expense reimbursements, if any, was above the median of the relevant peer group. The Board reviewed the fees and other expenses of the Fund with the Adviser and was satisfied that the overall expense structure of the Fund remained competitive. The Board will continue to monitor advisory fees and other expenses borne by the Fund.

Annual Shareholder Report

The Senior Officer noted that, considering the totality of the circumstances, and all of the factors referenced within his Evaluation, he had concluded that, subject to comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds was reasonable and that Federated appeared to provide appropriate advisory and administrative services to the Fund for the fees paid. Under these circumstances, no changes were recommended to, and no objection was raised to, the continuation of the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

Annual Shareholder Report

Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available from Federated's website at FederatedInvestors.com. To access this information from the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Proxy Voting Record Report (Form N-PX).” Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information from the “Products” section of Federated's website at FederatedInvestors.com. From the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Form N-Q.”

Annual Shareholder Report

Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Prime Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551105



28566 (7/12)

Federated is a registered trademark of Federated Investors, Inc.
2012  © Federated Investors, Inc.

Annual Shareholder Report

May 31, 2012


Ticker CTTXX

Not FDIC Insured

May Lose Value

No Bank Guarantee


Federated Treasury Cash Series

A Portfolio of Cash Trust Series, Inc.

CONTENTS

Portfolio of Investments Summary Tables (unaudited)

At May 31, 2012, the Fund's portfolio composition1 was as follows:

Portfolio Composition Percentage of
Total Net Assets
Repurchase Agreements 73.4%
U.S. Treasury Securities 26.5%
Other Assets and Liabilities — Net2 0.1%
TOTAL 100.0%

At May 31, 2012, the Fund's effective maturity3 schedule was as follows:

Securities With an
Effective Maturity of:		 Percentage of
Total Net Assets
1-7 Days 60.8%
8-30 Days 16.2%
31-90 Days 5.2%
91-180 Days 9.3%
181 Days or more 8.4%
Other Assets and Liabilities — Net2 0.1%
TOTAL 100.0%
1 See the Fund's Prospectus and Statement of Additional Information for a description of the types of securities in which the Fund invests.
2 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3 Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.
Annual Shareholder Report

Portfolio of Investments

May 31, 2012

Principal
Amount		 Value
U.S. Treasury – 26.5%
$75,000,000 United States Treasury Notes, 0.375%, 8/31/2012 75,042,634
25,000,000 United States Treasury Notes, 0.375%, 9/30/2012 25,022,779
70,000,000 United States Treasury Notes, 0.625%, 6/30/2012 70,029,721
23,000,000 United States Treasury Notes, 0.750% - 2.500%, 3/31/2013 23,348,485
71,000,000 United States Treasury Notes, 1.375%, 9/15/2012 71,248,966
49,000,000 United States Treasury Notes, 1.375%, 10/15/2012 49,222,715
25,500,000 United States Treasury Notes, 1.375%, 1/15/2013 25,695,533
41,500,000 United States Treasury Notes, 1.375%, 2/15/2013 41,856,131
32,000,000 United States Treasury Notes, 1.375%, 3/15/2013 32,291,977
35,000,000 United States Treasury Notes, 1.500%, 7/15/2012 35,059,465
57,000,000 United States Treasury Notes, 1.875%, 6/15/2012 57,039,153
20,500,000 United States Treasury Notes, 2.750%, 2/28/2013 20,888,550
28,000,000 United States Treasury Notes, 3.375%, 11/30/2012 28,446,806
25,000,000 United States Treasury Notes, 3.625%, 12/31/2012 25,499,130
42,500,000 United States Treasury Notes, 4.375%, 8/15/2012 42,869,360
TOTAL U.S. TREASURY 623,561,405
Repurchase Agreements – 73.4%
100,000,000 Interest in $350,000,000 joint repurchase agreement 0.19%, dated 5/31/2012 under which Bank of Montreal will repurchase securities provided as collateral for $350,001,847 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 10/31/2014 and the market value of those underlying securities was $357,001,989. 100,000,000
87,000,000 1 Interest in $1,000,000,000 joint repurchase agreement 0.13%, dated 3/21/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $1,000,325,000 on 6/19/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2041 and the market value of those underlying securities was $1,020,265,238. 87,000,000
44,000,000 1 Interest in $470,000,000 joint repurchase agreement 0.17%, dated 5/22/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $470,199,750 on 8/22/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2030 and the market value of those underlying securities was $479,418,190. 44,000,000
Annual Shareholder Report
Principal
Amount		 Value
$100,000,000 Interest in $3,000,000,000 joint repurchase agreement 0.18%, dated 5/31/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $3,000,015,000 on 6/1/2012. The securities provided as collateral at the end of the period were U.S. Treasury securities with various maturities to 11/30/2015 and the market value of those underlying securities was $3,059,551,075. 100,000,000
100,000,000 Interest in $3,000,000,000 joint repurchase agreement 0.18%, dated 5/31/2012 under which Barclays Capital, Inc. will repurchase securities provided as collateral for $3,000,015,000 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2042 and the market value of those underlying securities was $3,060,015,338. 100,000,000
84,000,000 1 Interest in $941,000,000 joint repurchase agreement 0.17%, dated 5/15/2012 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $941,133,308 on 6/15/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/28/2019 and the market value of those underlying securities was $959,892,541. 84,000,000
83,000,000 1 Interest in $943,000,000 joint repurchase agreement 0.17%, dated 5/17/2012 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $943,138,045 on 6/18/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2020 and the market value of those underlying securities was $961,923,636. 83,000,000
100,000,000 Interest in $1,185,000,000 joint repurchase agreement 0.19%, dated 5/31/2012 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $1,185,006,254 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 3/31/2019 and the market value of those underlying securities was $1,208,706,439. 100,000,000
86,593,000 Interest in $4,000,000,000 joint repurchase agreement 0.18%, dated 5/31/2012 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $4,000,020,000 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2039 and the market value of those underlying securities was $4,080,020,437. 86,593,000
85,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.16%, dated 5/31/2012 under which CS First Boston Corp. will repurchase securities provided as collateral for $1,000,031,111 on 6/7/2012. The securities provided as collateral at the end of the period held with JPMorgan Chase & Co., tri-party agent, were U.S. Treasury securities with various maturities to 7/15/2020 and the market value of those underlying securities was $1,020,006,085. 85,000,000
Annual Shareholder Report
Principal
Amount		 Value
$86,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.17%, dated 5/25/2012 under which CS First Boston Corp. will repurchase securities provided as collateral for $1,000,033,056 on 6/1/2012. The securities provided as collateral at the end of the period held with JPMorgan Chase & Co., tri-party agent, were U.S. Treasury securities with various maturities to 6/30/2014 and the market value of those underlying securities was $1,020,029,060. 86,000,000
100,000,000 Interest in $3,285,000,000 joint repurchase agreement 0.18%, dated 5/31/2012 under which CS First Boston Corp. will repurchase securities provided as collateral for $3,285,016,425 on 6/1/2012. The securities provided as collateral at the end of the period held with JPMorgan Chase & Co., tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2041 and the market value of those underlying securities was $3,350,704,316. 100,000,000
190,000,000 Interest in $2,600,000,000 joint repurchase agreement 0.14%, dated 5/30/2012 under which Deutsche Bank Securities, Inc. will repurchase securities provided as collateral for $2,600,070,778 on 6/6/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2040 and the market value of those underlying securities was $2,652,020,679. 190,000,000
184,000,000 Interest in $1,000,000,000 joint repurchase agreement 0.14%, dated 5/30/2012 under which Goldman Sachs & Co. will repurchase securities provided as collateral for $1,000,027,222 on 6/6/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 7/15/2019 and the market value of those underlying securities was $1,020,008,014. 184,000,000
100,000,000 Interest in $500,000,000 joint repurchase agreement 0.19%, dated 5/31/2012 under which Merrill Lynch, Pierce, Fenner and Smith will repurchase securities provided as collateral for $500,002,639 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2041 and the market value of those underlying securities was $510,002,730. 100,000,000
100,000,000 Interest in $405,520,000 joint repurchase agreement 0.19%, dated 5/31/2012 under which RBS Securities, Inc. will repurchase a security provided as collateral for $405,522,140 on 6/1/2012. The security provided as collateral at the end of the period held with JPMorgan Chase & Co., tri-party agent, was a U.S. Treasury security maturing on 2/15/2022 and the market value of that underlying security was $413,635,233. 100,000,000
Annual Shareholder Report
Principal
Amount		 Value
$100,000,000 Interest in $1,685,000,000 joint repurchase agreement 0.18%, dated 5/31/2012 under which Societe Generale, New York will repurchase securities provided as collateral for $1,685,008,425 on 6/1/2012. The securities provided as collateral at the end of the period held with The Bank of New York Mellon, tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2041 and the market value of those underlying securities was $1,718,708,642. 100,000,000
TOTAL REPURCHASE AGREEMENTS 1,729,593,000
TOTAL INVESTMENTS — 99.9%
(AT AMORTIZED COST)2 		2,353,154,405
OTHER ASSETS AND LIABILITIES - NET — 0.1%3 2,454,323
TOTAL NET ASSETS — 100% $2,355,608,728
1 Although the repurchase date is more than seven days after the date of purchase, the Fund has the right to terminate the repurchase agreement at any time with seven-days' notice.
2 Also represents cost for federal tax purposes.
3 Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at May 31, 2012.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1 — quoted prices in active markets for identical securities, including investment companies with daily net asset values, if applicable.

Level 2 — other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3 — significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of May 31, 2012, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Financial Highlights

(For a Share Outstanding Throughout Each Period)

Year Ended May 31 2012 2011 2010 2009 2008
Net Asset Value, Beginning of Period $1.00 $1.00 $1.00 $1.00 $1.00
Income From Investment Operations:
Net investment income  —   —   —  0.0032 0.0273
Net realized gain on investments 0.00001 0.00001 0.00001 0.0001  — 
TOTAL FROM INVESTMENT OPERATIONS 0.00001 0.00001 0.00001 0.0033 0.0273
Less Distributions:
Distributions from net investment income  —   —   —  (0.0032) (0.0273)
Distributions from net realized gain on investments (0.0000)1 (0.0000)1  —  (0.0001)  — 
TOTAL DISTRIBUTIONS (0.0000)1 (0.0000)1  —  (0.0033) (0.0273)
Net Asset Value, End of Period $1.00 $1.00 $1.00 $1.00 $1.00
Total Return2 0.00%3 0.00%3 0.00%3 0.32% 2.76%
Ratios to Average Net Assets:
Net expenses 0.10% 0.19% 0.21% 0.47% 1.04%
Net investment income 0.00% 0.00% 0.00% 0.15% 2.45%
Expense waiver/reimbursement4 0.98% 0.89% 0.87% 0.62% 0.05%
Supplemental Data:
Net assets, end of period (000 omitted) $2,355,609 $1,445,337 $1,339,308 $1,457,691 $712,164
1 Represents less than $0.0001.
2 Based on net asset value.
3 Represents less than 0.01%.
4 This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Assets and Liabilities

May 31, 2012

Assets:
Investment in repurchase agreements $1,729,593,000
Investment in securities 623,561,405
Total investment in securities, at amortized cost and fair value $2,353,154,405
Cash 78,464
Income receivable 2,849,712
Receivable for shares sold 100
TOTAL ASSETS 2,356,082,681
Liabilities:
Payable to adviser (Note 5) 197,815
Payable for shares redeemed 108,207
Payable for custodian fees 14,192
Payable for transfer and dividend disbursing agent fees and expenses 15,409
Payable for portfolio accounting fees 15,511
Payable for tax expense 108,909
Accrued expenses 13,910
TOTAL LIABILITIES 473,953
Net assets for 2,355,605,978 shares outstanding $2,355,608,728
Net Assets Consist of:
Paid-in capital $2,355,606,000
Accumulated net realized gain on investments 2,728
TOTAL NET ASSETS $2,355,608,728
Net Asset Value, Offering Price and Redemption
Proceeds Per Share:
($2,355,608,728 ÷ 2,355,605,978 shares outstanding), $0.001 par value, 12,500,000,000 shares authorized $1.00

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Operations

Year Ended May 31, 2012

Investment Income:
Interest $2,254,144
Expenses:
Investment adviser fee (Note 5) $11,480,689
Administrative fee (Note 5) 1,791,456
Custodian fees 89,811
Transfer and dividend disbursing agent fees and expenses 2,439,084
Directors'/Trustees' fees 11,343
Auditing fees 18,500
Legal fees 9,424
Portfolio accounting fees 156,057
Distribution services fee (Note 5) 2,296,138
Shareholder services fee (Note 5) 5,738,544
Account administration fee 1,601
Share registration costs 328,063
Printing and postage 121,683
Insurance premiums 8,085
Taxes 173,633
Miscellaneous 25,342
TOTAL EXPENSES 24,689,453
Waivers and Reimbursements: (Note 5)
Waiver of investment adviser fee $(11,480,689)
Waiver of administrative fee (44,095)
Waiver of transfer and dividend disbursing agent fees and expenses (2,233,973)
Waiver of distribution services fee (2,296,138)
Waiver of shareholder services fee (5,726,664)
Reimbursement of shareholder services fee (11,880)
Reimbursement of account administration fee (1,601)
Reimbursement of other operating expenses (640,269)
TOTAL WAIVERS AND REIMBURSEMENTS (22,435,309)
Net expenses 2,254,144
Net investment income  — 
Net realized gain on investments 3,088
Change in net assets resulting from operations $3,088

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Statement of Changes in Net Assets

Year Ended May 31 2012 2011
Increase (Decrease) in Net Assets
Operations:
Net investment income $ —  $ — 
Net realized gain on investments 3,088 2,417
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS 3,088 2,417
Distributions to Shareholders:
Distributions from net realized gain on investments (2,777) (1,182)
Share Transactions:
Proceeds from sale of shares 6,273,085,141 6,308,216,081
Net asset value of shares issued to shareholders in payment of distributions declared 2,715 1,172
Cost of shares redeemed (5,362,816,786) (6,202,189,037)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS 910,271,070 106,028,216
Change in net assets 910,271,381 106,029,451
Net Assets:
Beginning of period 1,445,337,347 1,339,307,896
End of period $2,355,608,728 $1,445,337,347

See Notes which are an integral part of the Financial Statements

Annual Shareholder Report

Notes to Financial Statements

May 31, 2012

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Treasury Cash Series (the “Fund”). The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is to provide current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate market value, the fair value of the portfolio securities will be determined under procedures established by and under the general supervision of the Board of Directors (the “Directors”).

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

Annual Shareholder Report

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective interest rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the year ended May 31, 2012, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of May 31, 2012, tax years 2009 through 2012 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed Delivery Transactions

The Fund may engage in when-issued or delayed delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated.

Annual Shareholder Report

3. CAPITAL STOCK

The following table summarizes capital stock activity:

Year Ended May 31 2012 2011
Shares sold 6,273,085,141 6,308,216,081
Shares issued to shareholders in payment of distributions declared 2,715 1,172
Shares redeemed (5,362,816,786) (6,202,189,037)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS 910,271,070 106,028,216

4. FEDERAL TAX INFORMATION

The tax character of distributions as reported on the Statement of Changes in Net Assets for the years ended May 31, 2012 and 2011, was as follows:

2012 2011
Ordinary income1 $2,777 $1,182
1 For tax purposes, short-term capital gain distributions are treated as ordinary income distributions.

As of May 31, 2012, the components of distributable earnings on a tax basis were as follows:

Undistributed ordinary income2 $2,728
2 For tax purposes, short-term capital gains are treated as ordinary income for distribution purposes.

5. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

Federated Investment Management Company is the Fund's investment adviser (the “Adviser”). The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee and/or reimburse certain operating expenses of the Fund. For the year ended May 31, 2012, the Adviser voluntarily waived its entire fee of $11,480,689 and voluntarily reimbursed $640,269 of other operating expenses. In addition, an affiliate of the Adviser waived $2,233,973 of transfer and dividend disbursing agent fees and expenses.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. The fee paid to FAS is based on the average aggregate daily net assets of certain Federated funds as specified below:

Administrative Fee Average Aggregate Daily Net Assets
of the Federated Funds
0.150% on the first $5 billion
0.125% on the next $5 billion
0.100% on the next $10 billion
0.075% on assets in excess of $20 billion
Annual Shareholder Report

The administrative fee received during any fiscal year shall be at least $150,000 per portfolio and $40,000 per each additional class of Shares. Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, the net fee paid to FAS was 0.076% of average daily net assets of the Fund. FAS waived $44,095 of its fee.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the year ended May 31, 2012, FSC voluntarily waived its entire fee of $2,296,138. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Shareholder Services Fee

The Fund may pay fees (“Service Fees”) up to 0.25% of the average daily net assets of the Fund to financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for Service Fees. For the year ended May 31, 2012, FSSC voluntarily reimbursed $11,880 of shareholder services fees and $1,601 of account administration fees. In addition, for the year ended May 31, 2012, unaffiliated third-party financial intermediaries waived $5,726,664 of shareholder services fees. This waiver can be modified or terminated at any time.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and its affiliates (which may include FSC, FAS and FSSC) have voluntarily agreed to waive their fees and/or reimburse expenses so that the total annual fund operating expenses (as shown in the financial highlights) paid by the Fund's Shares (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”) up to but not including the later of (the “Termination Date”): (a) August 1, 2013; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of the above companies.

Annual Shareholder Report

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of May 31, 2012, there were no outstanding loans. During the year ended May 31, 2012, the program was not utilized.

8. recent accounting pronouncements

In April 2011, the Financial Accounting Standards Board (FASB) released Accounting Standards Update (ASU) No. 2011-03, “Reconsideration of Effective Control for Repurchase Agreements.” This ASU amends FASB Accounting Standards Codification (ASC) Topic 860, “Transfers and Servicing”; specifically the criteria required to determine whether a repurchase agreement and similar agreements should be accounted for as sales of financial assets or secured borrowings with commitments. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-03 is not expected to have a material impact on the Fund's financial statements and the accompanying notes, net assets or results of operations.

In addition, in May 2011, FASB released ASU No. 2011-04, “Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” This ASU amends FASB ASC Topic 820, “Fair Value Measurement,” to establish common requirements for measuring fair value and for disclosing information about fair value measurements in accordance with GAAP. This ASU is effective for fiscal years and interim periods beginning after December 15, 2011. Management has concluded that the adoption of ASU No. 2011-04 is not expected to have a material impact on the Fund's financial statements and the accompanying notes.

Annual Shareholder Report

Report of Independent Registered Public Accounting Firm

TO THE BOARD OF DIRECTORS OF Cash trust Series, INc. AND SHAREHOLDERS Of Federated Treasury Cash Series:

We have audited the accompanying statement of assets and liabilities of Federated Treasury Cash Series (the “Fund”) (one of the portfolios constituting Cash Trust Series, Inc.), including the portfolio of investments, as of May 31, 2012, and the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of May 31, 2012, by correspondence with the custodian and others. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Federated Treasury Cash Series, a portfolio of Cash Trust Series, Inc. at May 31, 2012, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles.

Boston, Massachusetts
July 24, 2012

Annual Shareholder Report

Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or shareholder services fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from December 1, 2011 to May 31, 2012.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Annual Shareholder Report

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

Beginning
Account Value
12/1/2011		 Ending
Account Value
5/31/2012		 Expenses Paid
During Period1,2
Actual $1,000 $1,000.00 $0.55
Hypothetical (assuming a 5% return
before expenses)		 $1,000 $1,024.45 $0.56
1 Expenses are equal to the Fund's annualized net expense ratio of 0.11%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).
2 Actual and Hypothetical expenses paid during the period utilizing the Fund's current annualized net expense ratio of 1.05% (as reflected in the Notes to Financial Statements, Note 5 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect current expenses as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.
Annual Shareholder Report

Board of Directors and Corporation Officers

The Board of Directors is responsible for managing the Corporation's business affairs and for exercising all the Corporation's powers except those reserved for the shareholders. The following tables give information about each Director and the senior officers of the Fund. Where required, the tables separately list Directors who are “interested persons” of the Fund (i.e., “Interested” Directors) and those who are not (i.e., “Independent” Directors). Unless otherwise noted, the address of each person listed is Federated Investors Tower, 1001 Liberty Avenue, Pittsburgh, PA 15222. The address of all Independent Directors listed is 4000 Ericsson Drive, Warrendale, PA 15086-7561; Attention: Mutual Fund Board. As of December 31, 2011, the Corporation comprised four portfolio(s), and the Federated Fund Family consisted of 43 investment companies (comprising 134 portfolios). Unless otherwise noted, each Officer is elected annually. Unless otherwise noted, each Director oversees all portfolios in the Federated Fund Family and serves for an indefinite term. The Fund's Statement of Additional Information includes additional information about Corporation Directors and is available, without charge and upon request, by calling 1-800-341-7400.

Interested DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held and Previous Position(s)
John F. Donahue*
Birth Date: July 28, 1924
Director
Began serving: May 1989		 Principal Occupations: Director or Trustee of the Federated Fund Family; Chairman and Director, Federated Investors, Inc.; Chairman of the Federated Fund Family's Executive Committee.

Previous Positions: Chairman of the Federated Fund Family; Trustee, Federated Investment Management Company; Chairman and Director, Federated Investment Counseling.
J. Christopher Donahue*
Birth Date: April 11, 1949
President and Director
Began serving: May 1989		 Principal Occupations: Principal Executive Officer and President of the Federated Fund Family; Director or Trustee of some of the Funds in the Federated Fund Family; President, Chief Executive Officer and Director, Federated Investors, Inc.; Chairman and Trustee, Federated Investment Management Company; Trustee, Federated Investment Counseling; Chairman and Director, Federated Global Investment Management Corp.; Chairman, Federated Equity Management Company of Pennsylvania and Passport Research, Ltd. (investment advisory subsidiary of Federated); Trustee, Federated Shareholder Services Company; Director, Federated Services Company.

Previous Positions: President, Federated Investment Counseling; President and Chief Executive Officer, Federated Investment Management Company, Federated Global Investment Management Corp. and Passport Research, Ltd.

* Family relationships and reasons for “interested” status: John F. Donahue is the father of J. Christopher Donahue; both are “interested” due to their beneficial ownership of shares of Federated Investors, Inc. and the positions they hold with Federated and its subsidiaries.
Annual Shareholder Report

INDEPENDENT DIRECTORS Background

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Nicholas P. Constantakis, CPA
Birth Date: September 3, 1939
Director
Began serving: February 1998		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorship Held: Director, Chairman of the Audit Committee, and member of the Compensation Committee, Michael Baker Corporation (architecture, engineering and construction services).

Previous Position: Partner, Andersen Worldwide SC.

Qualifications: Public accounting and director experience.
John F. Cunningham
Birth Date: March 5, 1943
Director
Began serving: January 1999		 Principal Occupation: Director or Trustee of the Federated Fund Family.

Other Directorships Held: Chairman, President and Chief Executive Officer, Cunningham & Co., Inc. (strategic business consulting); Trustee Associate, Boston College.

Previous Positions: Director, Redgate Communications and EMC Corporation (computer storage systems); Chairman of the Board and Chief Executive Officer, Computer Consoles, Inc.; President and Chief Operating Officer, Wang Laboratories; Director, First National Bank of Boston; Director, Apollo Computer, Inc.

Qualifications: Business management and director experience.
Maureen Lally-Green
Birth Date: July 5, 1949
Director
Began serving: August 2009		 Principal Occupations: Director or Trustee of the Federated Fund Family; Director, Office of Church Relations, Diocese of Pittsburgh; Adjunct Professor of Law, Duquesne University School of Law.

Other Directorships Held: Director, Auberle; Member, Pennsylvania State Board of Education; Director, Saint Vincent College; Director, Ireland Institute of Pittsburgh; Chair and Director, UPMC Mercy Hospital; Regent, St. Vincent Seminary; Director, Epilepsy Foundation of Western and Central Pennsylvania; Director, Saint Thomas More Society, Allegheny County.

Previous Position: Pennsylvania Superior Court Judge.

Qualifications: Legal and director experience.
Peter E. Madden
Birth Date: March 16, 1942
Director
Began serving: August 1991		 Principal Occupation: Director or Trustee, and Chairman of the Board of Directors or Trustees, of the Federated Fund Family.

Previous Positions: Representative, Commonwealth of Massachusetts General Court; President, Chief Operating Officer and Director, State Street Bank and Trust Company and State Street Corporation (retired); Director, VISA USA and VISA International; Chairman and Director, Massachusetts Bankers Association; Director, Depository Trust Corporation; Director, The Boston Stock Exchange.

Qualifications: Business management, mutual fund services and director experience.
Annual Shareholder Report
Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years,
Other Directorships Held, Previous Position(s) and Qualifications
Charles F. Mansfield, Jr.
Birth Date: April 10, 1945
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee of the Federated Fund Family; Management Consultant.

Previous Positions: Chief Executive Officer, PBTC International Bank; Partner, Arthur Young & Company (now Ernst & Young LLP); Chief Financial Officer of Retail Banking Sector, Chase Manhattan Bank; Senior Vice President, HSBC Bank USA (formerly Marine Midland Bank); Vice President, Citibank; Assistant Professor of Banking and Finance, Frank G. Zarb School of Business, Hofstra University; Executive Vice President, DVC Group, Inc. (marketing, communications and technology).

Qualifications: Banking, business management, education and director experience.
Thomas M. O'Neill
Birth Date: June 14, 1951
Director
Began serving: October 2006		 Principal Occupations: Director or Trustee, Vice Chairman of the Audit Committee of the Federated Fund Family; Sole Proprietor, Navigator Management Company (investment and strategic consulting).

Other Directorships Held: Board of Overseers, Children's Hospital of Boston; Visiting Committee on Athletics, Harvard College; Board of Directors, Medicines for Humanity; Board of Directors, The Golisano Children's Museum of Naples, Florida.

Previous Positions: Chief Executive Officer and President, Managing Director and Chief Investment Officer, Fleet Investment Advisors; President and Chief Executive Officer, Aeltus Investment Management, Inc.; General Partner, Hellman, Jordan Management Co., Boston, MA; Chief Investment Officer, The Putnam Companies, Boston, MA; Credit Analyst and Lending Officer, Fleet Bank; Director and Consultant, EZE Castle Software (investment order management software); Director, Midway Pacific (lumber).

Qualifications: Business management, mutual fund, director and investment experience.
John S. Walsh
Birth Date: November 28, 1957
Director
Began serving: January 1999		 Principal Occupations: Director or Trustee, Chairman of the Audit Committee of the Federated Fund Family; President and Director, Heat Wagon, Inc. (manufacturer of construction temporary heaters); President and Director, Manufacturers Products, Inc. (distributor of portable construction heaters); President, Portable Heater Parts, a division of Manufacturers Products, Inc.

Previous Position: Vice President, Walsh & Kelly, Inc.

Qualifications: Business management and director experience.
Annual Shareholder Report

OFFICERS

Name
Birth Date
Positions Held with Corporation
Date Service Began		 Principal Occupation(s) for Past Five Years
and Previous Position(s)
John W. McGonigle
Birth Date: October 26, 1938
EXECUTIVE VICE PRESIDENT AND SECRETARY
Began serving: May 1989		 Principal Occupations: Executive Vice President and Secretary of the Federated Fund Family; Vice Chairman, Executive Vice President, Secretary and Director, Federated Investors, Inc.

Previous Positions: Trustee, Federated Investment Management Company and Federated Investment Counseling; Director, Federated Global Investment Management Corp., Federated Services Company and Federated Securities Corp.
Richard A. Novak
Birth Date: December 25, 1963
Treasurer
Began serving: January 2006		 Principal Occupations: Principal Financial Officer and Treasurer of the Federated Fund Family; Senior Vice President, Federated Administrative Services; Financial and Operations Principal for Federated Securities Corp., Edgewood Services, Inc. and Southpointe Distribution Services, Inc.

Previous Positions: Controller of Federated Investors, Inc.; Vice President, Finance of Federated Services Company; held various financial management positions within The Mercy Hospital of Pittsburgh; Auditor, Arthur Andersen & Co.
Richard B. Fisher
Birth Date: May 17, 1923
Vice Chairman
Began serving: August 2002		 Principal Occupations: Vice Chairman or Vice President of some of the Funds in the Federated Fund Family; Vice Chairman, Federated Investors, Inc.; Chairman, Federated Securities Corp.

Previous Positions: President and Director or Trustee of some of the Funds in the Federated Fund Family; Executive Vice President, Federated Investors, Inc.; Director and Chief Executive Officer, Federated Securities Corp.
Brian P. Bouda
Birth Date: February 28, 1947
CHIEF COMPLIANCE OFFICER AND SENIOR VICE PRESIDENT
Began serving: August 2004		 Principal Occupations: Senior Vice President and Chief Compliance Officer of the Federated Fund Family; Vice President and Chief Compliance Officer of Federated Investors, Inc. and Chief Compliance Officer of its subsidiaries. Mr. Bouda joined Federated in 1999 and is a member of the American Bar Association and the State Bar Association of Wisconsin.
Deborah A. Cunningham
Birth Date: September 15, 1959
Chief Investment Officer
Began serving: May 2004		 Principal Occupations: Deborah A. Cunningham has been the Fund's Portfolio Manager since January 1994. Ms. Cunningham was named Chief Investment Officer of money market products in 2004. She joined Federated in 1981 and has been a Senior Portfolio Manager since 1997 and an Executive Vice President of the Fund's Adviser since 2009. Ms. Cunningham has received the Chartered Financial Analyst designation and holds an M.S.B.A. in Finance from Robert Morris College.
Susan R. Hill
Birth Date: June 20, 1963
VICE PRESIDENT
Began serving: November 1998		 Principal Occupations: Susan R. Hill has been the Fund's Portfolio Manager since January 1994. She is Vice President of the Corporation. Ms. Hill joined Federated in 1990 and has been a Senior Portfolio Manager since 2003 and a Senior Vice President of the Fund's Adviser since 2005. Ms. Hill was a Portfolio Manager from 1994 until 2003 and served as Vice President of the Fund's Adviser from 1997 until 2004 and an Assistant Vice President of the Fund's Adviser from 1994 until 1997. Ms. Hill has received the Chartered Financial Analyst designation and holds an M.S. in Industrial Administration from Carnegie Mellon University.

Annual Shareholder Report

Evaluation and Approval of Advisory Contract – May 2012

Federated Treasury Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2012 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies exist, whether they have been shared with a fund and its shareholders; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent to which the Board members are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. Consistent with these judicial decisions, the Board also considered management fees (including any components thereof) charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

Annual Shareholder Report

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

Annual Shareholder Report

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant, given the high degree of competition in the mutual fund business. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a generally reliable indication of what consumers have found to be reasonable in the precise marketplace in which the Fund competes. In this regard, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes; different associated costs; different portfolio management techniques made necessary by different cash flows; and portfolio manager time spent in review of securities pricing. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory contracts.

The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn assisted the Board in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups are relevant in judging the reasonableness of proposed fees.

The Fund's performance fell below the median of the relevant peer group for the one-year period covered by the Evaluation. The Board discussed the Fund's performance with the Adviser and recognized the efforts being undertaken by the Adviser. The Board will continue to monitor these efforts and the performance of the Fund.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The Annual Shareholder Report

information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution or elimination of these voluntary waivers.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, although they may apply consistent allocation processes, the inherent difficulties in allocating costs (and the unavoidable arbitrary aspects of that exercise) and the lack of consensus on how to allocate those costs may render such allocation information unreliable. The allocation information was considered in the analysis by the Board but was determined to be of limited use.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer noted the limited availability of such information, but nonetheless concluded that Federated's profit margins did not appear to be excessive.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies, should they exist) were likely to be enjoyed by the fund complex as a whole. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size. The Senior Officer did not recommend institution of breakpoints in pricing Federated's fund advisory services at this time.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual fee rate and other expenses of the Fund with the Adviser and was satisfied that the overall expense structure of the Fund remained competitive.

Annual Shareholder Report

The Senior Officer noted that, considering the totality of the circumstances, and all of the factors referenced within his Evaluation, he had concluded that, subject to comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds was reasonable and that Federated appeared to provide appropriate advisory and administrative services to the Fund for the fees paid. Under these circumstances, no changes were recommended to, and no objection was raised to, the continuation of the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

Annual Shareholder Report

Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available from Federated's website at FederatedInvestors.com. To access this information from the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Proxy Voting Record Report (Form N-PX).” Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information from the “Products” section of Federated's website at FederatedInvestors.com. From the home page, select “All” under “Asset Classes.” Select a fund name and share class, if applicable, to go to the Fund Overview page. On the Fund Overview page, select the “Documents” tab. At the bottom of that page, select “Form N-Q.”

Annual Shareholder Report

Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

Federated Treasury Cash Series
Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551402



28567 (7/12)

Federated is a registered trademark of Federated Investors, Inc.
2012  © Federated Investors, Inc.

Item 2. Code of Ethics

 

(a) As of the end of the period covered by this report, the registrant has adopted a code of ethics (the "Section 406 Standards for Investment Companies - Ethical Standards for Principal Executive and Financial Officers") that applies to the registrant's Principal Executive Officer and Principal Financial Officer; the registrant's Principal Financial Officer also serves as the Principal Accounting Officer.

(c) Not Applicable

(d) Not Applicable

(e) Not Applicable

(f)(3) The registrant hereby undertakes to provide any person, without charge, upon request, a copy of the code of ethics. To request a copy of the code of ethics, contact the registrant at 1-800-341-7400, and ask for a copy of the Section 406 Standards for Investment Companies - Ethical Standards for Principal Executive and Financial Officers.

Item 3. Audit Committee Financial Expert

The registrant's Board has determined that each of the following members of the Board's Audit Committee is an “audit committee financial expert,” and is "independent," for purposes of this Item:   Nicholas P. Constantakis, Charles F. Mansfield, Jr., Thomas M. O'Neill and John S. Walsh. 

 

Item 4. Principal Accountant Fees and Services

 

(a) Audit Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2012 - $78,650

Fiscal year ended 2011 - $75,600

 

(b) Audit-Related Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2012 - $0

Fiscal year ended 2011 - $97

Travel to Audit Committee meeting.

 

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $0 and $0 respectively.

 

(c) Tax Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2012 - $0

Fiscal year ended 2011 - $0

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $ 0 and $ 0 respectively.

 

(d) All Other Fees billed to the registrant for the two most recent fiscal years:

Fiscal year ended 2012 - $0

Fiscal year ended 2011 - $0

Amount requiring approval of the registrant’s audit committee pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, $0 and $0 respectively.

 

(e)(1) Audit Committee Policies regarding Pre-approval of Services.

The Audit Committee is required to pre-approve audit and non-audit services performed by the independent auditor in order to assure that the provision of such services do not impair the auditor’s independence. Unless a type of service to be provided by the independent auditor has received general pre-approval, it will require specific pre-approval by the Audit Committee. Any proposed services exceeding pre-approved cost levels will require specific pre-approval by the Audit Committee.

Certain services have the general pre-approval of the Audit Committee. The term of the general pre-approval is 12 months from the date of pre-approval, unless the Audit Committee specifically provides for a different period. The Audit Committee will annually review the services that may be provided by the independent auditor without obtaining specific pre-approval from the Audit Committee and may grant general pre-approval for such services. The Audit Committee will revise the list of general pre-approved services from time to time, based on subsequent determinations. The Audit Committee will not delegate its responsibilities to pre-approve services performed by the independent auditor to management.

The Audit Committee has delegated pre-approval authority to its Chairman. The Chairman will report any pre-approval decisions to the Audit Committee at its next scheduled meeting. The Committee will designate another member with such pre-approval authority when the Chairman is unavailable.

 

AUDIT SERVICES

The annual Audit services engagement terms and fees will be subject to the specific pre-approval of the Audit Committee. The Audit Committee must approve any changes in terms, conditions and fees resulting from changes in audit scope, registered investment company (RIC) structure or other matters.

In addition to the annual Audit services engagement specifically approved by the Audit Committee, the Audit Committee may grant general pre-approval for other Audit Services, which are those services that only the independent auditor reasonably can provide. The Audit Committee has pre-approved certain Audit services, all other Audit services must be specifically pre-approved by the Audit Committee.

 

AUDIT-RELATED SERVICES

Audit-related services are assurance and related services that are reasonably related to the performance of the audit or review of the Company’s financial statements or that are traditionally performed by the independent auditor. The Audit Committee believes that the provision of Audit-related services does not impair the independence of the auditor, and has pre-approved certain Audit-related services, all other Audit-related services must be specifically pre-approved by the Audit Committee.

 

 

TAX SERVICES

The Audit Committee believes that the independent auditor can provide Tax services to the Company such as tax compliance, tax planning and tax advice without impairing the auditor’s independence. However, the Audit Committee will not permit the retention of the independent auditor in connection with a transaction initially recommended by the independent auditor, the purpose of which may be tax avoidance and the tax treatment of which may not be supported in the Internal Revenue Code and related regulations. The Audit Committee has pre-approved certain Tax services, all Tax services involving large and complex transactions must be specifically pre-approved by the Audit Committee.

 

ALL OTHER SERVICES

With respect to the provision of services other than audit, review or attest services the pre-approval requirement is waived if:

 

(1)The aggregate amount of all such services provided constitutes no more than five percent of the total amount of revenues paid by the registrant, the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant to its accountant during the fiscal year in which the services are provided;

 

(2)Such services were not recognized by the registrant, the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant at the time of the engagement to be non-audit services; and

 

(3)Such services are promptly brought to the attention of the Audit Committee of the issuer and approved prior to the completion of the audit by the Audit Committee or by one or more members of the Audit Committee who are members of the board of directors to whom authority to grant such approvals has been delegated by the Audit Committee.

 

The Audit Committee may grant general pre-approval to those permissible non-audit services classified as All Other services that it believes are routine and recurring services, and would not impair the independence of the auditor.

 

The SEC’s rules and relevant guidance should be consulted to determine the precise definitions of prohibited non-audit services and the applicability of exceptions to certain of the prohibitions.

 

PRE-APPROVAL FEE LEVELS

Pre-approval fee levels for all services to be provided by the independent auditor will be established annually by the Audit Committee. Any proposed services exceeding these levels will require specific pre-approval by the Audit Committee.

 

PROCEDURES

Requests or applications to provide services that require specific approval by the Audit Committee will be submitted to the Audit Committee by both the independent auditor and the Principal Accounting Officer and/or Internal Auditor, and must include a joint statement as to whether, in their view, the request or application is consistent with the SEC’s rules on auditor independence.

 

(e)(2) Percentage of services identified in items 4(b) through 4(d) that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X:

 

4(b)

Fiscal year ended 2012 – 0%

Fiscal year ended 2011 - 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

 

4(c)

Fiscal year ended 2012 – 0%

Fiscal year ended 2011 – 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

 

4(d)

Fiscal year ended 2012 – 0%

Fiscal year ended 2011 – 0%

Percentage of services provided to the registrants investment adviser and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were approved by the registrants audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X, 0% and 0% respectively.

 

(f) NA

 

(g) Non-Audit Fees billed to the registrant, the registrant’s investment adviser, and certain entities controlling, controlled by or under common control with the investment adviser:

Fiscal year ended 2012 - $377,220

Fiscal year ended 2011 - $320,093

 

(h) The registrant’s Audit Committee has considered that the provision of non-audit services that were rendered to the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant’s independence.

 

Item 5. Audit Committee of Listed Registrants

 

Not Applicable

 

Item 6. Schedule of Investments

 

(a) The registrant’s Schedule of Investments is included as part of the Report to Stockholders filed under Item 1 of this form.

 

(b) Not Applicable; Fund had no divestments during the reporting period covered since the previous Form N-CSR filing.

 

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

 

Not Applicable

 

Item 8. Portfolio Managers of Closed-End Management Investment Companies

 

Not Applicable

 

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

 

Not Applicable

 

Item 10. Submission of Matters to a Vote of Security Holders

 

Not Applicable

 

Item 11. Controls and Procedures

 

(a) The registrant’s President and Treasurer have concluded that the

registrant’s disclosure controls and procedures (as defined in rule 30a-3(c) under the Act) are effective in design and operation and are sufficient to form the basis of the certifications required by Rule 30a-(2) under the Act, based on their evaluation of these disclosure controls and procedures within 90 days of the filing date of this report on Form N-CSR.

 

(b) There were no changes in the registrant’s internal control over financial reporting (as defined in rule 30a-3(d) under the Act) during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

 

Item 12. Exhibits

 

(a)(1) Code of Ethics- Not Applicable to this Annual Report.

 

(a)(2) Certifications of Principal Executive Officer and Principal Financial Officer.

 

(a)(3) Not Applicable.

 

(b) Certifications pursuant to 18 U.S.C. Section 1350.

 

 

 

 

 

 

 

 

 

 

 

 

SIGNATURES

 

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

 

Registrant Cash Trust Series, Inc.

 

By /S/ Richard A. Novak

 

Richard A. Novak, Principal Financial Officer

 

Date July 19, 2012

 

 

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

 

 

By /S/ J. Christopher Donahue

 

J. Christopher Donahue, Principal Executive Officer

 

Date July 19, 2012

 

 

By /S/ Richard A. Novak

 

Richard A. Novak, Principal Financial Officer

 

Date July 19, 2012