497

MORGAN STANLEY INSTITUTIONAL FUND, INC.

522 Fifth Avenue

New York, New York 10036

VIA EDGAR

January 22, 2013

Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Re:Morgan Stanley Institutional Fund, Inc.

File Nos. 33-23166; 811-05624

Ladies and Gentlemen:

On behalf of Morgan Stanley Institutional Fund, Inc. (“Registrant”), we hereby submit for filing pursuant to Rule 497(e) under the Securities Act of 1933, as amended, exhibits containing interactive data format risk/return summary information for the Registrant. These exhibits contain the risk/return summary information in the prospectuses for the Registrant dated April 30, 2012. The purpose of this filing is to submit the XBRL information from the 497(e) filing dated January 14, 2013 for the Registrant.

If you have any questions, please feel free to contact me at 212.296.6983 (tel.) or 646.452.4799 (fax).

Very truly yours,

/s/ Tara Farrelly

Tara Farrelly

Assistant Secretary

Enclosures

cc:  Stefanie V. Chang Yu, Esq.

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INTERNATIONAL REAL ESTATE PORTFOLIO (Prospectus Summary): | INTERNATIONAL REAL ESTATE PORTFOLIO

International Real Estate Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

With respect to each of the International Real Estate Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P INTERNATIONAL REAL ESTATE PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P INTERNATIONAL REAL ESTATE PORTFOLIO	646	901	1,175	1,957

With respect to the International Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P INTERNATIONAL REAL ESTATE PORTFOLIO	Class P Return before Taxes	(24.34%)	[1]	(13.09%)	[1]	8.72%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Select Global Infrastructure Portfolio (Prospectus Summary): | Select Global Infrastructure Portfolio

Select Global Infrastructure Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Global Franchise and Select Global Infrastructure Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Select Global Infrastructure Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Select Global Infrastructure Portfolio	Class P	660	945	1,251	2,117

With respect to the Select Global Infrastructure Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Select Global Infrastructure Portfolio	Class P (commenced operations on 9/20/10) Return before Taxes	9.57%	[1]	11.53%	[1]	Sep. 20, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

GROWTH PORTFOLIO (Prospectus Summary): | GROWTH PORTFOLIO

Growth Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

With respect to each of the Global Discovery and Growth Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P GROWTH PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P GROWTH PORTFOLIO	618	815	1,028	1,641

With respect to the Growth Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P GROWTH PORTFOLIO	Class P Return before Taxes	(8.35%)	[1]	1.98%	[1]	2.61%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Global Opportunity Portfolio (Prospectus Summary): | Global Opportunity Portfolio

Global Opportunity Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the Global Opportunity and Opportunity Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Global Opportunity Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Global Opportunity Portfolio	670	974	1,300	2,222

With respect to the Global Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Global Opportunity Portfolio	Class P (commenced operations on 5/21/10) Return before Taxes	(10.14%)	[1]	12.23%	[1]	May 21, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Global Real Estate Portfolio (Prospectus Summary): | Global Real Estate Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Global Real Estate Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Real Estate and U.S. Real Estate Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Global Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Global Real Estate Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MRLBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

649

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

913

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,195

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,000

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 8/30/06) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(14.60%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(6.22%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

(3.01%)

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 30, 2006

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Global Advantage Portfolio (Prospectus Summary): | Global Advantage Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Global Advantage Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Advantage and Global Advantage Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Global Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Global Advantage Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MIGPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

674

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

989

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,325

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,274

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 12/28/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(5.14%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

(5.01%)

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 28, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Global Opportunity Portfolio (Prospectus Summary): | Global Opportunity Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Global Opportunity Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Opportunity and Opportunity Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Global Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Global Opportunity Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MGGPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

670

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

974

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,300

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,222

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 5/21/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(10.14%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

12.23%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

May 21, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

GLOBAL FRANCHISE PORTFOLIO (Prospectus Summary): | GLOBAL FRANCHISE PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Global Franchise Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Franchise and Select Global Infrastructure Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Global Franchise Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

GLOBAL FRANCHISE PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSFBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

646

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

901

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,175

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,957

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

3.24%

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

3.34%

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

9.56%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

International Advantage Portfolio (Prospectus Summary): | International Advantage Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

International Advantage Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the International Advantage Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the International Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

International Advantage Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MFAPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

670

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

974

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,300

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,222

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 12/28/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(6.71%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

(6.75%)

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 28, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

GROWTH PORTFOLIO (Prospectus Summary): | GROWTH PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Growth Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Discovery and Growth Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Growth Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

GROWTH PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSEGX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

618

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

815

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,028

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,641

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(8.35%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

1.98%

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

2.61%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

INTERNATIONAL REAL ESTATE PORTFOLIO (Prospectus Summary): | INTERNATIONAL REAL ESTATE PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

International Real Estate Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the International Real Estate Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the International Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

INTERNATIONAL REAL ESTATE PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

IERBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

646

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

901

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,175

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,957

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(24.34%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(13.09%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

8.72%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Advantage Portfolio (Prospectus Summary): | Advantage Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Advantage Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Advantage and Global Advantage Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Advantage Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MAPPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

650

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

915

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,200

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,010

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 5/21/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(0.43%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

12.23%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

May 21, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

INTERNATIONAL EQUITY PORTFOLIO (Prospectus Summary): | INTERNATIONAL EQUITY PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

International Equity Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the International Equity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

INTERNATIONAL EQUITY PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MIQBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

641

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

886

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,150

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,903

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(12.70%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(3.92%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

4.90%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

International Opportunity Portfolio (Prospectus Summary): | International Opportunity Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

International Opportunity Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the International Opportunity Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the International Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

International Opportunity Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MIOPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

660

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

945

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,251

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,117

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 3/31/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(15.05%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

1.33%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

INTERNATIONAL EQUITY PORTFOLIO (Prospectus Summary): | INTERNATIONAL EQUITY PORTFOLIO

International Equity Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P INTERNATIONAL EQUITY PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P INTERNATIONAL EQUITY PORTFOLIO	Class P	641	886	1,150	1,903

With respect to the International Equity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P INTERNATIONAL EQUITY PORTFOLIO	Class P Return before Taxes	(12.70%)	[1]	(3.92%)	[1]	4.90%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

EMERGING MARKETS DOMESTIC DEBT PORTFOLIO (Prospectus Summary): | EMERGING MARKETS DOMESTIC DEBT PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Emerging Markets Domestic Debt Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Emerging Markets Domestic Debt Portfolio
(the "Portfolio")

Expense, Heading

rr_ExpenseHeading

The first paragraph in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 13 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

The following replaces the "Shareholder Fees" table and related footnote thereto with respect to Class P and Class H shares only in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Operating Expenses, Caption

rr_OperatingExpensesCaption

The following replaces the "Annual Portfolio Operating Expenses" table and related footnotes thereto with respect to Class L shares only in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses—Annual Portfolio Operating Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following table replaces the "Example" table with respect to Class P, Class H and Class L shares only in the section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

The following table replaces the "Average Annual Total Returns" table with respect to Class P and Class H shares only in the section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

EMERGING MARKETS DOMESTIC DEBT PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

IEDBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

532

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

760

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,005

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,708

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 1/2/96) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(8.01%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

3.95%

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

8.99%

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

9.48%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 02, 1996

^[1]

EMERGING MARKETS DOMESTIC DEBT PORTFOLIO | Class H

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSEHX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.00%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

508

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

736

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

982

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,687

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class H (commenced operations on 1/2/08) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(7.71%)

^[2]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

none

^[2]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

none

^[2]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

3.96%

^[2]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 02, 2008

^[2]

EMERGING MARKETS DOMESTIC DEBT PORTFOLIO | Class L

Risk/Return:

rr_RiskReturnAbstract

Advisory Fee

rr_ManagementFeesOverAssets

0.75%

Distribution and/or Service (12b-1) Fee

rr_DistributionAndService12b1FeesOverAssets

0.50%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.44%

Total Annual Portfolio Operating Expenses

rr_ExpensesOverAssets

1.69%

^[4]

Fee Waiver and/or Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.34%)

^[4]

Total Annual Portfolio Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

1.35%

^[4]

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

137

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

428

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

739

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,624

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 4.25%.

[2] The historical performance of Class H shares has been restated to reflect the current maximum initial sales charge of 4.00%.

[3] The Board of Directors approved an amendment to the Distribution and Shareholder Services Plan reducing the distribution and shareholder services (12b-1) fee for the Portfolio's Class L shares from 0.75% to 0.50% of the average daily net assets of such Class, effective February 25, 2013. The Distribution and/or Service (12b-1) Fees shown in the table above have been restated to reflect such change.

[4] The Portfolio’s "Adviser," Morgan Stanley Investment Management Inc., has agreed to reduce its advisory fee and/or reimburse the Portfolio so that Total Annual Portfolio Operating Expenses, excluding certain investment related expenses, will not exceed 0.85% for Class I, 1.10% for Class P, 1.10% for Class H and 1.35% for Class L. The fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund’s Board of Directors acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.

XML

Global Advantage Portfolio (Prospectus Summary): | Global Advantage Portfolio

Global Advantage Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the Advantage and Global Advantage Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Global Advantage Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Global Advantage Portfolio	674	989	1,325	2,274

With respect to the Global Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Global Advantage Portfolio	Class P (commenced operations on 12/28/10) Return before Taxes	(5.14%)	[1]	(5.01%)	[1]	Dec. 28, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Global Real Estate Portfolio (Prospectus Summary): | Global Real Estate Portfolio

Global Real Estate Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

With respect to each of the Global Real Estate and U.S. Real Estate Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Global Real Estate Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Global Real Estate Portfolio	649	913	1,195	2,000

With respect to the Global Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Global Real Estate Portfolio	Class P (commenced operations on 8/30/06) Return before Taxes	(14.60%)	[1]	(6.22%)	[1]	(3.01%)	[1]	Aug. 30, 2006	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Opportunity Portfolio (Prospectus Summary): | Opportunity Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Opportunity Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Opportunity and Opportunity Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Opportunity Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MEGPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

634

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

865

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,115

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,827

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 5/21/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(5.93%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

none

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

none

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

10.69%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

May 21, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO (Prospectus Summary): | ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO

Active International Allocation Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO	Class P	636	871	1,125	1,849

With respect to the Active International Allocation Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO	Class P Return before Taxes	(19.22%)	[1]	(4.93%)	[1]	4.01%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO (Prospectus Summary): | ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Active International Allocation Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Active International Allocation Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

ACTIVE INTERNATIONAL ALLOCATION PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSIBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

636

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

871

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,125

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,849

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(19.22%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(4.93%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

4.01%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

EMERGING MARKETS PORTFOLIO (Prospectus Summary): | EMERGING MARKETS PORTFOLIO

Emerging Markets Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P EMERGING MARKETS PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P EMERGING MARKETS PORTFOLIO	Class P	670	974	1,300	2,222

With respect to the Emerging Markets Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P EMERGING MARKETS PORTFOLIO	Class P Return before Taxes	(22.90%)	[1]	(1.09%)	[1]	12.08%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Asian Equity Portfolio (Prospectus Summary): | Asian Equity Portfolio

Asian Equity Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Asian Equity Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Asian Equity Portfolio	Class P	689	1,033	1,400	2,428

With respect to the Asian Equity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Asian Equity Portfolio	Class P (commenced operations on 12/28/10) Return before Taxes	(21.40%)	[1]	(19.76%)	[1]	Dec. 28, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Opportunity Portfolio (Prospectus Summary): | Opportunity Portfolio

Opportunity Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the Global Opportunity and Opportunity Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Opportunity Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Opportunity Portfolio	634	865	1,115	1,827

With respect to the Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Opportunity Portfolio	Class P (commenced operations on 5/21/10) Return before Taxes	(5.93%)	[1]	none	[1]	none	[1]	10.69%	[1]	May 21, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

U.S. REAL ESTATE PORTFOLIO (Prospectus Summary): | U.S. REAL ESTATE PORTFOLIO

U.S. Real Estate Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

With respect to each of the Global Real Estate and U.S. Real Estate Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P U.S. REAL ESTATE PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P U.S. REAL ESTATE PORTFOLIO	647	904	1,180	1,968

With respect to the U.S. Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P U.S. REAL ESTATE PORTFOLIO	Class P Return before Taxes	(0.27%)	[1]	(3.02%)	[1]	10.11%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

SMALL COMPANY GROWTH PORTFOLIO (Prospectus Summary): | SMALL COMPANY GROWTH PORTFOLIO

Small Company Growth Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

With respect to each of the Small Company Growth Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"    

Shareholder Fees	Class P SMALL COMPANY GROWTH PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P SMALL COMPANY GROWTH PORTFOLIO	650	915	1,200	2,010

With respect to the Small Company Growth Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P SMALL COMPANY GROWTH PORTFOLIO	Class P Return before Taxes	(14.07%)	[1]	(0.83%)	[1]	4.85%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

International Advantage Portfolio (Prospectus Summary): | International Advantage Portfolio

International Advantage Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the International Advantage Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P International Advantage Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P International Advantage Portfolio	670	974	1,300	2,222

With respect to the International Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P International Advantage Portfolio	Class P (commenced operations on 12/28/10) Return before Taxes	(6.71%)	[1]	(6.75%)	[1]	Dec. 28, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	Other
Document Period End Date	dei_DocumentPeriodEndDate	Jan. 14, 2013
Registrant Name	dei_EntityRegistrantName	MORGAN STANLEY INSTITUTIONAL FUND INC
Central Index Key	dei_EntityCentralIndexKey	0000836487
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Jan. 14, 2013
Document Effective Date	dei_DocumentEffectiveDate	Jan. 14, 2013
Prospectus Date	rr_ProspectusDate	Apr. 30, 2012

XML

INTERNATIONAL SMALL CAP PORTFOLIO (Prospectus Summary): | INTERNATIONAL SMALL CAP PORTFOLIO

International Small Cap Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P INTERNATIONAL SMALL CAP PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P INTERNATIONAL SMALL CAP PORTFOLIO	Class P	660	945	1,251	2,117

With respect to the International Small Cap Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P INTERNATIONAL SMALL CAP PORTFOLIO	Class P (commenced operations on 10/21/08) Return before Taxes	(22.83%)	[1]	none	[1]	none	[1]	4.48%	[1]	Oct. 21, 2008	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

U.S. REAL ESTATE PORTFOLIO (Prospectus Summary): | U.S. REAL ESTATE PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

U.S. Real Estate Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Real Estate Portfolio
International Real Estate Portfolio
U.S. Real Estate Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 22 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Real Estate and U.S. Real Estate Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the U.S. Real Estate Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

U.S. REAL ESTATE PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MUSDX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

647

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

904

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,180

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

1,968

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(0.27%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(3.02%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

10.11%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

INTERNATIONAL SMALL CAP PORTFOLIO (Prospectus Summary): | INTERNATIONAL SMALL CAP PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

International Small Cap Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the International Small Cap Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

INTERNATIONAL SMALL CAP PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSCPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

660

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

945

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,251

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,117

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 10/21/08) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(22.83%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

none

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

none

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

4.48%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 21, 2008

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Asian Equity Portfolio (Prospectus Summary): | Asian Equity Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Asian Equity Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Asian Equity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Asian Equity Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MEQPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

689

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

1,033

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,400

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,428

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 12/28/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(21.40%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

(19.76%)

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 28, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Advantage Portfolio (Prospectus Summary): | Advantage Portfolio

Advantage Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Advantage Portfolio
Global Advantage Portfolio
International Advantage Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the Advantage and Global Advantage Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Advantage Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Advantage Portfolio	650	915	1,200	2,010

With respect to the Advantage Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Advantage Portfolio	Class P (commenced operations on 5/21/10) Return before Taxes	(0.43%)	[1]	12.23%	[1]	May 21, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Global Discovery Portfolio (Prospectus Summary): | Global Discovery Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Global Discovery Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Discovery and Growth Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Global Discovery Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Global Discovery Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MGDPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

679

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

1,003

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,350

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,325

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 12/28/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(12.79%)

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

(12.94%)

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 28, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

SMALL COMPANY GROWTH PORTFOLIO (Prospectus Summary): | SMALL COMPANY GROWTH PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Small Company Growth Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Small Company Growth Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"    

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Small Company Growth Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

SMALL COMPANY GROWTH PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MSSMX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

650

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

915

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,200

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,010

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(14.07%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(0.83%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

4.85%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

EMERGING MARKETS PORTFOLIO (Prospectus Summary): | EMERGING MARKETS PORTFOLIO

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Emerging Markets Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Active International Allocation, Asian Equity, Emerging Markets, International Equity and International Small Cap Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Emerging Markets Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

EMERGING MARKETS PORTFOLIO | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MMKBX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)

rr_RedemptionFeeOverRedemption

(2.00%)

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

670

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

974

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,300

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,222

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

(22.90%)

^[1]

Average Annual Returns, 5 Years

rr_AverageAnnualReturnYear05

(1.09%)

^[1]

Average Annual Returns, 10 Years

rr_AverageAnnualReturnYear10

12.08%

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Global Discovery Portfolio (Prospectus Summary): | Global Discovery Portfolio

Global Discovery Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Discovery Portfolio
Growth Portfolio
Small Company Growth Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 32 of this Prospectus.

With respect to each of the Global Discovery and Growth Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P Global Discovery Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P Global Discovery Portfolio	679	1,003	1,350	2,325

With respect to the Global Discovery Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P Global Discovery Portfolio	Class P (commenced operations on 12/28/10) Return before Taxes	(12.79%)	[1]	(12.94%)	[1]	Dec. 28, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

International Opportunity Portfolio (Prospectus Summary): | International Opportunity Portfolio

International Opportunity Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Global Opportunity Portfolio
International Opportunity Portfolio
Opportunity Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 25 of this Prospectus.

With respect to each of the International Opportunity Portfolio, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P International Opportunity Portfolio
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P International Opportunity Portfolio	660	945	1,251	2,117

With respect to the International Opportunity Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns":  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P International Opportunity Portfolio	Class P (commenced operations on 3/31/10) Return before Taxes	(15.05%)	[1]	1.33%	[1]	Mar. 31, 2010	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Apr. 30, 2012

Select Global Infrastructure Portfolio (Prospectus Summary): | Select Global Infrastructure Portfolio

Risk/Return:

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Select Global Infrastructure Portfolio

Supplement Text

ck0000836487_SupplementTextBlock

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

Expense Breakpoint, Discounts

rr_ExpenseBreakpointDiscounts

For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H.

Expense Breakpoint, Minimum Investment Required Amount

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

Expense, Heading

rr_ExpenseHeading

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

Expense, Narrative

rr_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

With respect to each of the Global Franchise and Select Global Infrastructure Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Expense Example, Heading

rr_ExpenseExampleHeading

The following tables replace the "Example" tables with respect to Class P shares only in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Example:"  

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

With respect to the Select Global Infrastructure Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Supplement Closing

ck0000836487_SupplementClosingTextBlock

Please retain this supplement for future reference.

Select Global Infrastructure Portfolio | Class P

Risk/Return:

rr_RiskReturnAbstract

Trading Symbol

dei_TradingSymbol

MTIPX

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

Expense Example, By Year, Column

rr_ExpenseExampleByYearColumnName

Class P

Expense Example, With Redemption, 1 Year

rr_ExpenseExampleYear01

660

Expense Example, With Redemption, 3 Years

rr_ExpenseExampleYear03

945

Expense Example, With Redemption, 5 Years

rr_ExpenseExampleYear05

1,251

Expense Example, With Redemption, 10 Years

rr_ExpenseExampleYear10

2,117

Average Annual Returns, Label

rr_AverageAnnualReturnLabel

Class P (commenced operations on 9/20/10) Return before Taxes

Average Annual Returns, 1 Year

rr_AverageAnnualReturnYear01

9.57%

^[1]

Average Annual Returns, Since Inception

rr_AverageAnnualReturnSinceInception

11.53%

^[1]

Average Annual Returns, Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 20, 2010

^[1]

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.

XML

EMERGING MARKETS DOMESTIC DEBT PORTFOLIO (Prospectus Summary): | EMERGING MARKETS DOMESTIC DEBT PORTFOLIO

Emerging Markets Domestic Debt Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Emerging Markets Domestic Debt Portfolio
(the "Portfolio")

The first paragraph in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 13 of this Prospectus.

The following replaces the "Shareholder Fees" table and related footnote thereto with respect to Class P and Class H shares only in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees EMERGING MARKETS DOMESTIC DEBT PORTFOLIO	Class P	Class H
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	4.25%	4.00%
Redemption Fee (as a percentage of the amount redeemed on redemptions made within 30 days of purchase)	2.00%	2.00%

The following replaces the "Annual Portfolio Operating Expenses" table and related footnotes thereto with respect to Class L shares only in the section of the Prospectus entitled "Portfolio Summary—Fees and Expenses—Annual Portfolio Operating Expenses:"  

Annual Fund Operating Expenses		Class L EMERGING MARKETS DOMESTIC DEBT PORTFOLIO
Advisory Fee		0.75%
Distribution and/or Service (12b-1) Fee	[1]	0.50%
Other Expenses		0.44%
Total Annual Portfolio Operating Expenses	[2]	1.69%
Fee Waiver and/or Expense Reimbursement	[2]	(0.34%)
Total Annual Portfolio Operating Expenses After Fee Waiver and/or Expense Reimbursement	[2]	1.35%

The following table replaces the "Example" table with respect to Class P, Class H and Class L shares only in the section of the Prospectus entitled "Portfolio Summary—Example:"  

Expense Example EMERGING MARKETS DOMESTIC DEBT PORTFOLIO (USD $)	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P	532	760	1,005	1,708
Class H	508	736	982	1,687
Class L	137	428	739	1,624

The following table replaces the "Average Annual Total Returns" table with respect to Class P and Class H shares only in the section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns EMERGING MARKETS DOMESTIC DEBT PORTFOLIO	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years		Average Annual Returns, Since Inception		Average Annual Returns, Inception Date
Class P	Class P (commenced operations on 1/2/96) Return before Taxes	(8.01%)	[1]	3.95%	[1]	8.99%	[1]	9.48%	[1]	Jan. 02, 1996	[1]
Class H	Class H (commenced operations on 1/2/08) Return before Taxes	(7.71%)	[2]	none	[2]	none	[2]	3.96%	[2]	Jan. 02, 2008	[2]

Please retain this supplement for future reference.

[1] The Board of Directors approved an amendment to the Distribution and Shareholder Services Plan reducing the distribution and shareholder services (12b-1) fee for the Portfolio's Class L shares from 0.75% to 0.50% of the average daily net assets of such Class, effective February 25, 2013. The Distribution and/or Service (12b-1) Fees shown in the table above have been restated to reflect such change.

[2] The Portfolio’s "Adviser," Morgan Stanley Investment Management Inc., has agreed to reduce its advisory fee and/or reimburse the Portfolio so that Total Annual Portfolio Operating Expenses, excluding certain investment related expenses, will not exceed 0.85% for Class I, 1.10% for Class P, 1.10% for Class H and 1.35% for Class L. The fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund’s Board of Directors acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 4.25%.

[2] The historical performance of Class H shares has been restated to reflect the current maximum initial sales charge of 4.00%.

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GLOBAL FRANCHISE PORTFOLIO (Prospectus Summary): | GLOBAL FRANCHISE PORTFOLIO

Global Franchise Portfolio

Prospectus Supplement

January 14, 2013

Morgan Stanley Institutional Fund, Inc.

Supplement dated January 14, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2012 of:

Active International Allocation Portfolio
Asian Equity Portfolio
Emerging Markets Portfolio
Global Franchise Portfolio
International Equity Portfolio
International Small Cap Portfolio
Select Global Infrastructure Portfolio
(collectively, the "Portfolios")

The first paragraph in each Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses" is hereby deleted and replaced with the following:  

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For shareholders of Class P and Class H shares, you may qualify for sales charge discounts if the cumulative net asset value ("NAV") of Class P or Class H shares of the Portfolio purchased in a single transaction, together with the NAV of all Class P or Class H shares of a portfolio of Morgan Stanley Institutional Fund, Inc. (the "Fund") or of a portfolio of Morgan Stanley Institutional Fund Trust held in related accounts, amounts to $25,000 or more with respect to Class P and $50,000 or more with respect to Class H. More information about these and other discounts is available from your financial adviser and in the "Shareholder Information—How To Purchase Class P and Class H Shares" section on page 52 of this Prospectus.

With respect to each of the Global Franchise and Select Global Infrastructure Portfolios, the following table replaces the "Shareholder Fees" table with respect to Class P shares only in each such Portfolio's section of the Prospectus entitled "Portfolio Summary—Fees and Expenses:"  

Shareholder Fees	Class P GLOBAL FRANCHISE PORTFOLIO
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.25%

Expense Example (USD $)	Expense Example, By Year, Column	Expense Example, With Redemption, 1 Year	Expense Example, With Redemption, 3 Years	Expense Example, With Redemption, 5 Years	Expense Example, With Redemption, 10 Years
Class P GLOBAL FRANCHISE PORTFOLIO	Class P	646	901	1,175	1,957

With respect to the Global Franchise Portfolio, the following table replaces the "Average Annual Total Returns" table with respect to Class P shares only in such Portfolio's section of the Prospectus entitled "Portfolio Summary—Performance Information—Average Annual Total Returns:"  

Average Annual Total Returns	Average Annual Returns, Label	Average Annual Returns, 1 Year		Average Annual Returns, 5 Years		Average Annual Returns, 10 Years
Class P GLOBAL FRANCHISE PORTFOLIO	Class P Return before Taxes	3.24%	[1]	3.34%	[1]	9.56%	[1]

Please retain this supplement for future reference.

[1] The historical performance of Class P shares has been restated to reflect the current maximum initial sales charge of 5.25%.