SmallCap Blend Fund

	Class A	Class B	Class C
Ticker Symbol(s)	PLLAX	PLLBX	PSMCX

Principal Funds, Inc. Summary Prospectus February 29, 2012 amended April 20, 2012

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/prospectus. You can also get this information at no cost by calling 1-800-222-5852 or by sending an email request to prospectus@principalfunds.com.

This Summary Prospectus incorporates by reference the Statutory Prospectus for Classes A, B, C, and P shares dated February 29, 2012, as supplemented on March 16, 2012, March 29, 2012, April 9, 2012, and April 20, 2012, and the Statement of Additional Information dated February 29, 2012, as supplemented on March 16, 2012 and April 9, 2012 (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 page 194, of the Fund’s prospectus and “Multiple Class Structure” beginning on page 129 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 (as a percentage of offering price)	5.50%	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of dollars subject to charge)	1.00%	5.00%	1.00%

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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, 2011	Class A	Class B	Class C
Management Fees	0.75%	0.75%	0.75%
Distribution and/or Service (12b-1) Fees	0.25	1.00	1.00
Other Expenses	0.40	0.97	1.18
Acquired Fund Fees and Expenses	0.02	0.02	0.02
Total Annual Fund Operating Expenses	1.42%	2.74%	2.95%
Expense Reimbursement(1)	0.05	0.43	0.85
Total Annual Fund Operating Expenses after Expense Reimbursement	1.37%	2.31%	2.10%

⁽¹⁾  Principal Management Corporation ("Principal"), the investment advisor, has contractually agreed to limit the Fund’s expenses attributable to Class A, Class B, and Class C shares and, if necessary, pay expenses normally payable by the Fund, excluding interest expense and Acquired Fund Fees and Expenses, through the period ending February 28, 2014. 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 1.35% for Class A, 2.29% for Class B, and 2.08% for Class C shares. It is expected that the expense limit will continue through the period disclosed; however, Principal Funds, Inc. and Principal, the parties to the agreement, may agree to terminate the expense limit prior to the end of the period.

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	$682	$ 964	$1,274	$2,149
Class B	$734	$1,159	$1,564	$3,000
Class C	$313	$ 733	$1,385	$3,134

You would pay the following expenses if you did not redeem your shares:

	1 year	3 years	5 years	10 years
Class A	$682	$964	$1,274	$2,149
Class B	$234	$759	$1,364	$3,000
Class C	$213	$733	$1,385	$3,134

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 76.1% of the average value of its portfolio.

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Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets in equity securities of companies with small market capitalizations (those with market capitalizations similar to companies in the Russell 2000^® Index (as of December 31, 2011, this range was between approximately $4.5 million and $3.7 billion)) at the time of purchase.

The Fund invests in equity securities with value and/or growth characteristics and constructs an investment portfolio that has a "blend" of equity securities with these characteristics. Investing in value equity securities is an investment strategy that emphasizes buying equity securities that appear to be undervalued. The growth orientation selection emphasizes buying equity securities of companies whose potential for growth of capital and earnings is expected to be above average. The Fund does not have a policy of preferring one of these categories over the other.

Principal Risks

The Fund may be an appropriate investment for investors seeking long-term growth of capital and willing to accept the potential for volatile fluctuations in the value of investments.

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. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund, in alphabetical order, are:

Equity Securities Risk. Equity securities (common, convertible preferred stocks and other 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. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.

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.

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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 '03	19.65%
Lowest return for a quarter during the period of the bar chart above:	Q4 '08	-26.29%

Average Annual Total Returns
For the periods ended December 31, 2011	1 Year	5 Years	10 Years
Class A Return Before Taxes	-7.54%	-2.58%	3.91%
Class A Return After Taxes on Distributions	-7.54%	-2.90%	3.44%
Class A Return After Taxes on Distribution and Sale of Fund Shares	-4.90%	-2.22%	3.37%
Class B Return Before Taxes	-8.02%	-2.81%	3.60%
Class C Return Before Taxes	-3.92%	-2.14%	3.74%
Russell 2000 Index (reflects no deduction for fees, expenses, or taxes)	-4.18%	0.15%	5.62%

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

·Phil Nordhus (since 2006), Portfolio Manager

·Brian Pattinson (since 2011), Portfolio Manager

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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 $1,200 annually if the initial $1,000 minimum has not been met.

Effective March 1, 2010, Class B shares of the Fund are no longer 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 (regular mail) or 30 Dan Road, Canton, MA 02021-2809 (overnight mail); calling us at 1-800-222-5852; 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 website for more information.

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