MIDCAP BLEND FUND 

	Class A	Class B	Class C
Ticker Symbol(s)	PEMGX	PRMBX	PMBCX

       Principal Funds, Inc. Summary Prospectus March 1, 2010 

Before you invest, you may want to review the Fund's prospectus, which contains more information about the Fund 

and its risks. You can find the Fund's prospectus and other information about the Fund online at 

www.principalfunds.com/investor/forms/prospectuses.htm. You can also get this information at no cost by calling 1- 

800-222-5852 or by sending an email to prospectus@principalfunds.com. 

This Summary Prospectus incorporates by reference the Statutory Prospectus for Class A, B, and C shares dated 

March 1, 2010 and the Statement of Additional Information dated March 1, 2010 (which may be obtained in the same 

manner as the Prospectus). 

Objective: The Fund seeks long-term growth of capital. 

Fees and Expenses of the Fund 

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify 

for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Principal 

Funds, Inc. More information about these and other discounts is available from your financial professional and in 

“Choosing a Share Class” and “The Costs of Investing” beginning on pages 259 and 232, respectively, of the Fund’s 

prospectus and “Multiple Class Structure” beginning on page 116 of the Fund’s Statement of Additional Information. 

Shareholder Fees (fees paid directly from your investment)
	Class A	Class B	Class C
Maximum Sales Charge (Load) Imposed on Purchases	5.50%	None	None
(as a percentage of offering price)
Maximum Deferred Sales Charge (Load)	1.00%	5.00%	1.00%
(as a percentage of dollars subject to charge)
Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)
For the year ended October 31, 2009	Class A	Class B	Class C
Management Fees	0.65%	0.65%	0.65%
Distribution and/or Service (12b-1) Fees	0.25%	1.00%	1.00%
Other Expenses	0.33%	0.63%	0.89%
Total Annual Fund Operating Expenses	1.23%	2.28%	2.54%
Expense Reimbursement	0.01%	0.05%	0.59%
Net Expenses	1.22%	2.23%	1.95%

Principal has contractually agreed to reduce the Fund's expenses attributable to Class A shares by 0.01% and Class B 

shares by 0.05% (expressed as a percent of average net asset on a daily basis) through the period ending 

February 28, 2011. 

Principal has contractually agreed to limit the Fund’s expenses attributable to Class C shares and, if necessary, pay 

expenses normally payable by the Fund, excluding interest expense, through the period ending February 28, 2011. 

The expense limit will maintain a total level of operating expenses (expressed as a percent of average net assets on 

an annualized basis) not to exceed 1.95% for Class C. 

Example 

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other 

mutual funds. 

       The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of 

       your shares at the end of those periods. The Example assumes conversion of the Class B shares to Class A 

       shares after the eighth year. The Example also assumes that your investment has a 5% return each year and that 

       the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on 

       these assumptions your costs would be: 

	1 year	3 years	5 years	10 years
Class A	$667	$ 918	$1,187	$1,956
Class B	$726	$1,107	$1,415	$2,347
Class C	$298	$ 725	$1,289	$2,824
You would pay the following expenses if you did not redeem your shares:
	1 year	3 years	5 years	10 years
Class A	$667	$918	$1,187	$1,956
Class B	$226	$707	$1,215	$1,247
Class C	$198	$725	$1,289	$2,824
Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). 

A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares 

are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the 

example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 

12.9% of the average value of its portfolio. 

Investor Profile: The Fund may be an appropriate investment for investors seeking long-term growth of capital and 

                                               willing to accept the potential for short-term fluctuations in the value of investments. 

Principal Investment Strategies 

The Fund invests primarily in equity securities of medium capitalization companies. Under normal circumstances, the 

Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of 

companies with medium market capitalizations (those with market capitalizations similar to companies in the Russell 

Midcap^® Index (as of the most recent calendar year end, this range was between approximately $0.03 billion and 

$15.5 billion) at the time of purchase. Market capitalization is defined as total current market value of a company’s 

outstanding common stock. 

In selecting securities for investment, Principal Global Investors, LLC (“PGI”) looks at stocks with value and/or growth 

characteristics and constructs an investment portfolio that has a “blend” of stocks with these characteristics. In 

managing the assets of the Fund, PGI does not have a policy of preferring one of these categories to the other. The 

value orientation emphasizes buying stocks at less than their inherent value and avoiding stocks whose price has 

been artificially built up. The growth orientation emphasizes buying stocks of companies whose potential for growth of 

capital and earnings is expected to be above average. 

PGI believes that superior stock selection is the key to consistent out-performance. PGI seeks to achieve superior 

stock selection by systematically evaluating company fundamentals and in-depth original research. 

PGI focuses its stock selections on established companies that it believes have a sustainable competitive advantage. 

PGI constructs a portfolio that is “benchmark aware” in that it is sensitive to the sector (companies with similar 

characteristics) and security weightings of its benchmark. 

The Fund may purchase securities issued as part of, or a short period after, companies’ initial public offerings and may 

at times dispose of those shares shortly after their acquisition. 

Principal Risks 

The value of your investment in the Fund changes with the value of the Fund’s investments. Many factors affect that 

value, and it is possible to lose money by investing in the Fund. The principal risks of investing in the Fund, in 

alphabetical order, are: 

Equity Securities Risk. Equity securities (common, preferred, and convertible preferred stocks and securities whose 

values are tied to the price of stocks, such as rights, warrants and convertible debt securities) could decline in value if 

the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal 

market segment(s), such as large cap, mid cap or small cap stocks, or growth or value stocks, may underperform 

other market segments or the equity markets as a whole. Investments in smaller companies and mid-size companies 

may involve greater risk and price volatility than investments in larger, more mature companies. 

Growth Stock Risk. Market prices of growth stocks are often more sensitive than other securities to earnings 

expectations. 

Initial Public Offerings ("IPOs") Risk. The market for IPO shares may be volatile, continued access to IPO offerings 

cannot be assured, and a fund may dispose of IPO shares shortly after their acquisition. 

Underlying Fund Risk. An underlying fund to a fund of funds may experience relatively large redemptions or 

investments as the fund of funds periodically reallocates or rebalances its assets. These transactions may cause the 

underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times 

it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund 

performance. 

Value Stock Risk. The market may not recognize the intrinsic value of value stocks for a long time, or they may be 

appropriately priced at the time of purchase. 

Performance 

The following information provides an indication of the risks of investing in the Fund. The bar chart shows the 

investment returns of the Fund’s Class A shares for each full calendar year of operations for 10 years (or, if shorter, 

the life of the Fund). These annual returns do not reflect sales charges; if they did, results would be lower. The table 

shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life 

of the Fund), how the Fund’s average annual total returns compare to the returns of one or more broad-based market 

indices. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the 

future. You may get updated performance information online at www.principalfunds.com or by calling 1-800-222-5852. 

Class A and B shares commenced operations on June 28, 2005, and Class C shares were first sold on January 16, 

2007. The returns for Class A, B, and C shares, for the periods prior to those dates, are based on the performance of 

the R-3 Class shares adjusted to reflect the fees and expenses of Class A, B, and C shares. The adjustments result in 

performance for such periods that is no higher than the historical performance of the R-3 Class shares. R-3 Class 

shares were first sold on December 6, 2000. 

Total Returns as of December 31 each year (Class A shares) 

 

Highest return for a quarter during the period of the bar chart above:	Q2 ‘09	17.51%
Lowest return for a quarter during the period of the bar chart above:	Q4 ‘08	-23.89%
Average Annual Total Returns
For the periods ended December 31, 2009	1 Year	5 Years	Life of Fund
Class A Return Before Taxes	25.18%	2.15%	5.06%
Class A Return After Taxes on Distributions	25.12%	1.18%	4.34%
Class A Return After Taxes on Distribution and Sale of Fund Shares	16.46%	1.80%	4.34%
Class B Return Before Taxes	26.09%	2.50%	5.38%
Class C Return Before Taxes	30.37%	2.42%	4.87%
Russell Midcap Index (reflects no deduction for fees, expenses, or taxes)	40.48%	2.43%	4.81%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not
reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ
from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-
deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class
A shares only and would be different for Class B and Class C shares.
Management
Investment Advisor: Principal Management Corporation
Sub-Advisor(s) and Portfolio Manager(s):
Principal Global Investors, LLC
•	K. William Nolin (since 2000), Portfolio Manager
Purchase and Sale of Fund Shares
Purchase minimums per fund (some exceptions apply):
•	Initial Investment	$1,000
	• For accounts with an Automatic Investment Plan (AIP)	$100
•	Subsequent Investments	$100
	• For accounts with an AIP, the subsequent automatic investments must total $1200 annually if the initial
	$1,000 minimum has not been met.

Effective March 1, 2010, Class B shares of the Fund will no longer be available for purchase, except through 

exchanges and dividend reinvestments. 

You may purchase or redeem shares on any business day (normally any day when the New York Stock Exchange is 

open for regular trading) through your Financial Professional; by sending a written request to Principal Funds at P.O. 

Box 8024, Boston, MA 02266-8024; calling us at 800-222-5852; or accessing our website (www.principalfunds.com). 

Tax Information 

The Fund's distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, 

unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement 

account. 

Payments to Broker-Dealers and Other Financial Intermediaries. 

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank, insurance company, 

investment adviser, etc.), the Fund and its related companies may pay the intermediary for the sale of Fund shares 

and related services. These payments may create a conflict of interest by influencing the broker-dealer or other 

intermediary and your salesperson to recommend the Fund over another investment, or to recommend one share 

class of the Fund over another share class. Ask your salesperson or visit your financial intermediary's Web site for 

more information.