MainStay International Equity Fund - Summary Prospectus February 26, 2010,
as revised on
April 1, 2010

TICKER SYMBOLS
Class A: MSEAX	Class I: MSIIX	Class R3: MIFRX
Class B: MINEX	Class R1: MIERX	Investor Class: MINNX
Class C: MIECX	Class R2: MIRRX

MSIE01a-04/10
28

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 by going online to mainstayinvestments.com/documents, by calling 800-MAINSTAY (624-6782) or by sending an e-mail to MainStayShareholderServices@nylim.com. The Fund's Prospectus and Statement of Additional Information, both dated February 26, 2010, and most recent report to shareholders, dated October 31, 2009, are all incorporated by reference into this Summary Prospectus.

Investment Objective

The Fund seeks to provide long-term growth of capital commensurate with an acceptable level of risk by investing in a portfolio consisting primarily of non-U.S. equity securities. Current income is a secondary objective.

Fees and Expenses of the Fund

The table below 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 the MainStay Funds. More information about these and other discounts is available from your financial professional and in the "Information on Sales Charges" section on page 58 of the Prospectus and in the "Alternative Sales Arrangements" section on page 122 of the Statement of Additional Information.

	Investor Class	Class A	Class B	Class C	Class I	Class R1	Class R2	Class R3
Shareholder Fees (fees paid directly from your investment)
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	5.50%	5.50%	None	None	None	None	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of the lesser of the original offering price or redemption proceeds)	None	None	5.00%	1.00%	None	None	None	None
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management Fees (as an annual percentage of the Fund's daily net assets)1	0.91%	0.91%	0.91%	0.91%	0.91%	0.91%	0.91%	0.91%
Distribution and/or Service (12b-1) Fees	0.25%	0.25%	1.00%	1.00%	None	None	0.25%	0.50%
Other Expenses	0.70%	0.26%	0.71%	0.69%	0.26%	0.36%	0.38%	0.36%
Acquired (Underlying) Fund Fees and Expenses	0.02%	0.02%	0.02%	0.02%	0.02%	0.02%	0.02%	0.02%
Total Annual Fund Operating Expenses	1.88%	1.44%	2.64%	2.62%	1.19%	1.29%	1.56%	1.79%

1 The management fee is an annual percentage of the Fund's average daily net assets as follows: 0.90% on assets up to $500 million and 0.85% on assets in excess of $500 million, plus a fee for fund accounting services previously provided by New York Life Investment Management LLC ("New York Life Investments") under a separate fund accounting agreement. This addition to the management fee amounted to 0.02% of the Fund's average daily net assets, but did not result in a net increase in the Fund's "Total Annual Fund Operating Expenses."

Example

The 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 (except as indicated with respect to Class B and Class C). 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 expenses would be:

Expenses after	Investor		Class A		Class B				Class C				Class I		Class R1		Class R2		Class R3
	Class				Assuming no redemption		Assuming redemption at end of each period		Assuming no redemption		Assuming redemption at end of each period
1 year	$	730	$	689	$	267	$	767	$	265	$	365	$	121	$	131	$	159	$	182
3 years	$	1,108	$	980	$	820	$	1,120	$	814	$	814	$	378	$	409	$	493	$	563
5 years	$	1,510	$	1,294	$	1,400	$	1,600	$	1,390	$	1,390	$	654	$	708	$	850	$	970
10 years	$	2,630	$	2,179	$	2,789	$	2,789	$	2,954	$	2,954	$	1,443	$	1,556	$	1,856	$	2,105

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 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 88% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests in those companies that meet the quality and valuation criteria of MacKay Shields LLC, the Fund's Subadvisor.

The Fund normally invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in equity securities of issuers, wherever organized, which do business mainly outside the U.S. It invests in securities of companies which do business in a variety of countries, with a minimum of five countries other than the U.S. This includes countries with established economies as well as emerging market countries that the Subadvisor believes present favorable opportunities.

Investment Process: The Subadvisor seeks to identify investment opportunities by pursuing a bottom-up, stock picking investment discipline. It performs research on identified companies to assess their business and investment prospects, paying attention to the generation and utilization of cash flows, the returns on invested capital, and the potential to generate shareholder value in the future. The Fund may not perform as well as its peers or benchmark during periods when the stock market favors the securities of buinesses with low-quality earnings, and/or those that have weak or high-risk business models and/or weak balance sheets. Allocations to countries are a result of the bottom-up stock selection process.

The Fund may buy and sell currency on a spot basis and enter into foreign currency forward contracts for risk management. In addition, the Fund may buy or sell foreign currency options, securities and securities index options and enter into swap agreements and futures contracts and related options, which are types of derivatives. These techniques may be used for any legally permissible purpose, including to increase the Fund's return or to reduce the risk of loss of (hedge) certain of its holdings.

The Subadvisor may sell a security if it no longer believes the security will contribute to meeting the investment objective of the Fund. In considering whether to sell a security, the Subadvisor may evaluate, among other things, if the security has reached its target price, if the investment thesis is invalidated, or if superior opportunities to redeploy exist or emerge.

Principal Risks

Loss of Money Risk: Before considering an investment in the Fund, you should understand that you could lose money.

Market Changes Risk: The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or poor security selection, which could cause the Fund to underperform other funds with similar objectives.

Common Stock Risk: Investments in common stocks and other equity securities are particularly subject to the risk of changing economic, stock market, industry and company conditions and the risks inherent in the portfolio managers' ability to anticipate changes that can adversely affect the value of the Fund's holdings.

Foreign Securities Risk: Investments in foreign securities are subject to risks that differ from those of U.S. issuers. These risk factors include: fluctuating currency values; less liquid trading markets; greater price volatility; political and economic instability; less publicly available information about issuers; changes in U.S. or foreign tax or currency laws; and changes in monetary policy. Foreign securities may be more difficult to sell than U.S. securities.

Investments in foreign securities may involve difficulties in receiving or interpreting financial and economic information, imposition of taxes, higher brokerage and custodian fees, currency rate fluctuations or exchange controls or other government restrictions, including seizure or nationalization of foreign deposits or assets. There may also be difficulty in invoking legal protections across borders. Some of these risks may cause the Fund's share price to be more volatile than that of a U.S. only mutual fund. The Fund may also incur higher expenses and costs when making foreign investments, which could affect the Fund's total return. The risks of foreign securities are likely to be greater in emerging market countries than in foreign countries with developed securities markets and more advanced regulatory regimes. Among other things, emerging market countries may have economic structures that are less mature and political systems that are less stable. Moreover, emerging market countries may have less developed securities markets, high inflation, and rapidly changing interest and currency exchange rates. Exchange rate movements can be large and can endure for extended periods of time, affecting either favorably or unfavorably the value of the Fund's assets.

Derivatives Risk: The Fund may lose money using derivatives, regardless of the purpose for using such instruments. Using derivatives may increase the volatility of the Fund's NAV and may involve a small investment relative to the risk assumed.

Recent Market Events Risk: Domestic and international markets have experienced a period of acute stress starting in the financial sector and then moving to other sectors of the world economy. This stress has resulted in extreme volatility in equity markets and stock prices. In some cases, the prices of certain stocks have declined sharply even though the financial condition or prospects of that company remain sound. These market conditions add significantly to the risk of short-term volatility of the Fund.

Past Performance

The following bar chart and tables indicate some of the risks of investing in the Fund. The bar chart shows you how the Fund's calendar year performance has varied over the last ten years. Sales loads are not reflected in the bar chart. If they were, returns would be less than those shown. The average annual total returns table shows how the Fund's average annual total returns (before and after taxes) for the one-, five- and ten-year periods compare to those of a broad-based securities market index. The Fund has selected the Morgan Stanley Capital International Europe, Australasia and Far East ("MSCI EAFE") Index as its primary benchmark index. The MSCI EAFE Index consists of international stocks representing the developed world outside of North America.

Performance data for the classes varies based on differences in their fee and expense structures. Performance figures for Class I, R1 and R2 shares, each of which was first offered on January 2, 2004, include the historical performance of Class B shares through January 1, 2004. Performance figures for Class R3 shares, first offered on April 28, 2006, include the historical performance of Class B shares through April 27, 2006. Performance figures for Investor Class shares, first offered on February 28, 2008, include the historical performance of Class A shares through February 27, 2008. Performance for newer share classes is adjusted for differences in certain contractual expenses and fees. Unadjusted, the performance shown for the newer classes might have been lower. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Annual Returns, Class B Shares

(by calendar year 2000-2009)

Best Quarter
2Q/03	17.23%
Worst Quarter
1Q/01	-14.02%

Average Annual Total Returns (for the periods ended December 31, 2009)
	1 year	5 years	10 years
Return Before Taxes
Investor Class	11.63%	3.85%	1.70%
Class A	11.98%	3.94%	1.74%
Class B	12.29%	3.92%	1.51%
Class C	16.25%	4.22%	1.51%
Class I	18.89%	5.62%	2.69%
Class R1	18.71%	5.47%	2.56%
Class R2	18.48%	5.27%	2.34%
Class R3	18.20%	4.93%	2.06%
Return After Taxes on Distributions
Class B	12.26%	2.76%	0.77%
Return After Taxes on Distributions and Sale of Fund Shares
Class B	8.81%	3.21%	1.15%
MSCI EAFE® Index (reflects no deductions for fees, expenses, or taxes)	31.78%	3.54%	1.17%

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. In some cases, the return after taxes may exceed the return before taxes due to an assumed benefit from any losses on a sale of shares at the end of the measurement period. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns shown are for Class B shares. After-tax returns for the other share classes may vary.

Management

New York Life Investments serves as the Fund's Manager. MacKay Shields LLC serves as the Fund's Subadvisor.

Subadvisor	Portfolio Managers	Service Date
MacKay Shields LLC	Rupal Bhansali, Senior Managing Director	Since 2001

How to Purchase and Sell Shares

You may purchase or sell shares of the Fund on any day the Fund is open for business by contacting your financial intermediary or other financial institution, or by contacting the Fund by telephone at 800-MAINSTAY (624-6782), by mail at MainStay Funds, P.O. Box 8401, Boston, MA 02266-8401 or by accessing our website at mainstayinvestments.com. Generally, an initial investment minimum of $1,000 applies if you invest in Investor Class, Class B, or Class C shares, $25,000 for Class A shares and $5,000,000 for individual investors in Class I shares investing directly (i) with MainStay Investments; or (ii) through certain private banks and trust companies that have an agreement with NYLIFE Distributors LLC or its affiliates. A subsequent investment minimum of $50 applies to investments in Investor Class, Class B and Class C shares. However, for Investor Class, Class B, or Class C shares purchased through AutoInvest, a monthly systematic investment plan, a $500 initial investment minimum ($50 for subsequent purchases) applies. Class R1, Class R2, Class R3 shares and institutional shareholders in Class I shares have no initial or subsequent investment minimums.

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.

Compensation to Broker-Dealers and Other Financial Intermediaries

If you purchase Fund shares through a broker-dealer or other financial intermediary (such as a bank), 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 individual financial adviser to recommend the Fund over another investment. Ask your individual financial adviser or visit your financial intermediary's website for more information. For additional information about compensation to financial intermediaries, please see the section entitled "Compensation to Dealers" in the "Shareholder Guide" section on page 59 of the Prospectus.