497

Bingham McCutchen LLP

One Federal Street

Boston, MA 02110

January 11, 2013

VIA EDGAR

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re: Western Asset Institutional Cash Reserves (the “Fund”), a series of Legg Mason Partners Institutional Trust (the “Registrant”)

File Nos. 33-49552 and 811-6740

Ladies and Gentlemen:

On behalf of the Registrant and pursuant to Rule 497(c) under the Securities Act of 1933, as amended, attached for filing are exhibits containing in interactive data format the risk/return summary information that appears in the Fund’s Prospectus relating to Investor Shares, dated December 28, 2012, as filed pursuant to Rule 497(c) on January 2, 2013.

Please call the undersigned at (617) 951-8381 with any comments or questions relating to the filing.

Sincerely,

/s/ Mari A. Wilson

Mari A. Wilson

Enclosures

cc: Rosemary D. Emmens, Legg Mason & Co., LLC

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	LEGG MASON PARTNERS INSTITUTIONAL TRUST
Prospectus Date	rr_ProspectusDate	Dec. 28, 2012
Document Creation Date	dei_DocumentCreationDate	Jan. 02, 2013

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	LEGG MASON PARTNERS INSTITUTIONAL TRUST
Prospectus Date	rr_ProspectusDate	Dec. 28, 2012
Investor | Western Asset Institutional Cash Reserves
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Western Asset Institutional Cash Reserves
Objective [Heading]	rr_ObjectiveHeading	Investment objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The fund’s investment objective is to provide shareholders with liquidity and as high a level of current income as is consistent with preservation of capital.
Expense [Heading]	rr_ExpenseHeading	Fees and expenses of the fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The accompanying table describes the fees and expenses that you may pay if you buy and hold Investor Shares of the fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder fees (fees paid directly from your investment) (%)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment) (%)
Expenses Represent Both Master and Feeder [Text]	rr_ExpensesRepresentBothMasterAndFeeder	The fund invests in securities through an underlying fund: Prime Cash Reserves Portfolio. The information above reflects the direct expenses of the fund and its allocated share of expenses of Prime Cash Reserves Portfolio.
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	“Other expenses” for Investor Shares are estimated for the current fiscal year. Actual expenses may differ from estimates.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes: You invest $10,000 in the fund for the time periods indicated Your investment has a 5% return each year and the fund’s operating expenses remain the same You reinvest all distributions and dividends without a sales charge Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	Number of years you own your shares ($)
Expense Example Closing [Text Block]	rr_ExpenseExampleClosingTextBlock	The fund invests in securities through an underlying fund: Prime Cash Reserves Portfolio. The information above reflects the direct expenses of the fund and its allocated share of expenses of Prime Cash Reserves Portfolio.
Strategy [Heading]	rr_StrategyHeading	Principal investment strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The fund is a money market fund which invests in high quality, U.S. dollar-denominated short-term debt securities that, at the time of purchase, are rated by one or more rating agencies in the highest short-term rating category or, if not rated, are determined by the subadviser to be of equivalent quality. The fund may invest in all types of money market instruments, including bank obligations, commercial paper and asset-backed securities, structured investments, repurchase agreements and other short-term debt securities. These instruments may be issued or guaranteed by all types of issuers, including U.S. and foreign banks and other private issuers, the U.S. government or any of its agencies or instrumentalities, U.S. states and municipalities, or foreign governments. These securities may pay interest at fixed, floating or adjustable rates, or may be issued at a discount. The fund may invest without limit in bank obligations, such as certificates of deposit, fixed time deposits and bankers’ acceptances. The fund generally limits its investments in foreign securities to U.S. dollar denominated obligations of issuers, including banks and foreign governments, located in the major industrialized countries, although with respect to bank obligations, the branches of the banks issuing the obligations may be located in The Bahamas or the Cayman Islands. As a money market fund, the fund tries to maintain a share price of $1.00, and must follow strict rules as to the credit quality, liquidity, diversification and maturity of its investments. Where required by these rules, the fund’s subadviser or Board of Trustees (the “Board”) will decide whether a security should be held or sold in the event of credit downgrades or certain other events occurring after purchase.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	Risks associated with concentration in the banking industry. The fund may invest a significant portion of its assets in obligations that are issued or backed by U.S. and non-U.S. banks, and thus will be more susceptible to negative events affecting the worldwide banking industry.
Risk [Heading]	rr_RiskHeading	Certain risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. Additionally, you should be aware that a very small number of money market funds in other fund complexes have, in the past, “broken the buck,” which means that investors did not receive $1.00 per share for their investment in those funds, and any money market fund may do so in the future. You should also be aware that the fund’s manager and its affiliates are under no obligation to provide financial support to the fund or take other measures to ensure that you receive $1.00 per share for your investment in the fund. You should not invest in the fund with the expectation that any such action will be taken. There is no assurance that the fund will meet its investment objective. The fund could underperform other short-term debt instruments or money market funds, or you could lose money, as a result of risks such as: Market and interest rate risk. There may be changes in interest rates, lack of liquidity or other disruptions in the bond markets or other adverse market events and conditions. The financial crisis that began in 2008 has caused a significant decline in the value and liquidity of many securities of issuers worldwide. In response to the crisis, the U.S. and other governments and the Federal Reserve and certain foreign central banks have taken steps to support financial markets. The withdrawal of this support, failure of efforts in response to the crisis, or investor perception that these efforts are not succeeding could negatively affect financial markets generally as well as the value and liquidity of certain securities. In addition, policy and legislative changes in the United States and in other countries are changing many aspects of financial regulation. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time. Credit risk. An issuer or obligor of a security held by the fund or a counterparty to a financial contract with the fund may default or its credit may be downgraded, or the value of assets underlying a security may decline. Yield risk. The amount of income received by the fund will go up or down depending on day-to-day variations in short-term interest rates, and when interest rates are very low the fund’s expenses could absorb all or a significant portion of the fund’s income. If interest rates increase, the fund’s yield may not increase proportionately. For example, the fund’s manager may discontinue any temporary voluntary fee limitation or recoup amounts previously waived and/or reimbursed. In addition, the recent adoption of more stringent regulations governing the management of money market funds could have a negative effect on the fund’s yield. Risk of increase in expenses. Your actual costs of investing in the fund may be higher than the expenses shown in “Annual fund operating expenses” for a variety of reasons. For example, expense ratios may be higher than those shown if average net assets are lower than estimated, or if a fee limitation is changed or terminated. Structured securities risk. The payment and credit qualities of structured securities derive from their underlying assets, and they may behave in ways not anticipated by the fund, or they may not receive tax, accounting or regulatory treatment anticipated by the fund. Risks associated with concentration in the banking industry. The fund may invest a significant portion of its assets in obligations that are issued or backed by U.S. and non-U.S. banks, and thus will be more susceptible to negative events affecting the worldwide banking industry. Foreign investments risk. The fund’s investments in securities of foreign issuers or issuers with significant exposure to foreign markets involve additional risk. Foreign countries in which the fund may invest may have markets that are less liquid, less regulated and more volatile than U.S. markets. The value of the fund’s investments may decline because of factors affecting the particular issuer as well as foreign markets and issuers generally, such as unfavorable government actions, and political or financial instability. Lack of information may also affect the value of these securities. Prepayment or call risk. Many issuers have a right to prepay their securities. If interest rates fall, an issuer may exercise this right. If this happens, the fund will be forced to reinvest prepayment proceeds at a time when yields on securities available in the market are lower than the yield on the prepaid security. Extension risk. If interest rates rise, repayments of fixed income securities may occur more slowly than anticipated by the market. This may drive the prices of these securities down because their interest rates are lower than the current interest rate and they remain outstanding longer. Portfolio selection risk. The value of your investment may decrease if the subadviser’s judgment about the quality, relative yield or value of, or market trends affecting, a particular security or sector, or about interest rates generally, is incorrect. Redemption risk. The fund may experience heavy redemptions, particularly during periods of declining or illiquid markets, that could cause the fund to liquidate its assets at inopportune times or at a loss or depressed value and that could affect the fund’s ability to maintain a $1.00 share price. In addition, the fund may suspend redemptions when permitted by applicable regulations. These risks are discussed in more detail later in this Prospectus or in the statement of additional information (“SAI”).
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	Additionally, you should be aware that a very small number of money market funds in other fund complexes have, in the past, “broken the buck,” which means that investors did not receive $1.00 per share for their investment in those funds, and any money market fund may do so in the future. You should also be aware that the fund’s manager and its affiliates are under no obligation to provide financial support to the fund or take other measures to ensure that you receive $1.00 per share for your investment in the fund. You should not invest in the fund with the expectation that any such action will be taken.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Institutional Shares (formerly Class O shares), a class of the fund that is invested in the same portfolio of securities as Investor Shares. The table shows the average annual total returns of Institutional Shares. No performance information is presented for Investor Shares because there were no Investor Shares outstanding during the calendar years shown. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated performance information available at the fund’s website, http://www.leggmason.com/individualinvestors/products/mutual-funds/annualized_performance (select share class), or by calling the fund at 1-877-721-1926 or 1-203-703-6002. The fund’s past performance is not necessarily an indication of how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart shows changes in the fund’s performance from year to year for Institutional Shares (formerly Class O shares), a class of the fund that is invested in the same portfolio of securities as Investor Shares.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-877-721-1926 or 1-203-703-6002
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	http://www.leggmason.com/individualinvestors/products/mutual-funds/annualized_performance (select share class)
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The fund’s past performance is not necessarily an indication of how the fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Total returns (%)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Calendar Years ended December 31 Best quarter (12/31/2006): 1.32 Worst quarter (09/30/2011): 0.03 The year-to-date return as of the most recent calendar quarter, which ended 09/30/2012, was 0.15
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	The bar chart shows changes in the fund’s performance from year to year for Institutional Shares (formerly Class O shares), a class of the fund that is invested in the same portfolio of securities as Investor Shares. The table shows the average annual total returns of Institutional Shares. No performance information is presented for Investor Shares because there were no Investor Shares outstanding during the calendar years shown. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ.
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns (for periods ended December 31, 2011) (%)
Investor | Western Asset Institutional Cash Reserves | Investor Shares
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.20%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.10%
Other expenses	rr_OtherExpensesOverAssets	0.03%	[1]
Total annual fund operating expenses	rr_ExpensesOverAssets	0.33%
1 year	rr_ExpenseExampleYear01	34
3 years	rr_ExpenseExampleYear03	106
5 years	rr_ExpenseExampleYear05	186
10 years	rr_ExpenseExampleYear10	418
Investor | Western Asset Institutional Cash Reserves | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
2003	rr_AnnualReturn2003	1.08%
2004	rr_AnnualReturn2004	1.30%
2005	rr_AnnualReturn2005	3.19%
2006	rr_AnnualReturn2006	5.02%
2007	rr_AnnualReturn2007	5.27%
2008	rr_AnnualReturn2008	2.98%
2009	rr_AnnualReturn2009	0.62%
2010	rr_AnnualReturn2010	0.21%
2011	rr_AnnualReturn2011	0.17%
Year to Date Return, Label	rr_YearToDateReturnLabel	The year-to-date return as of the most recent calendar quarter
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.15%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2006
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.32%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.03%
1 year	rr_AverageAnnualReturnYear01	0.17%
5 years	rr_AverageAnnualReturnYear05	1.83%
Since Inception	rr_AverageAnnualReturnSinceInception	2.17%
Inception date	rr_AverageAnnualReturnInceptionDate	Oct. 02, 2002

[1] "Other expenses" for Investor Shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

XML

Investor | Western Asset Institutional Cash Reserves

Western Asset Institutional Cash Reserves

Investment objective

The fund’s investment objective is to provide shareholders with liquidity and as high a level of current income as is consistent with preservation of capital.

Fees and expenses of the fund

The accompanying table describes the fees and expenses that you may pay if you buy and hold Investor Shares of the fund.

Shareholder fees (fees paid directly from your investment) (%)

Shareholder Fees	Investor Western Asset Institutional Cash Reserves Investor Shares
Maximum sales charge (load) imposed on purchases	none
Maximum deferred sales charge (load)	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of
your investment) (%)

Annual Fund Operating Expenses		Investor Western Asset Institutional Cash Reserves Investor Shares
Management fees		0.20%
Distribution and service (12b-1) fees		0.10%
Other expenses	[1]	0.03%
Total annual fund operating expenses		0.33%

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes:

• You invest $10,000 in the fund for the time periods indicated

• Your investment has a 5% return each year and the fund’s operating expenses remain the same

• You reinvest all distributions and dividends without a sales charge

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Number of years you own your shares ($)

Expense Example (USD $)	1 year	3 years	5 years	10 years
Investor Western Asset Institutional Cash Reserves Investor Shares	34	106	186	418

The fund invests in securities through an underlying fund: Prime Cash Reserves Portfolio. The information above reflects the direct expenses of the fund and its allocated share of expenses of Prime Cash Reserves Portfolio.

Principal investment strategies

The fund is a money market fund which invests in high quality, U.S. dollar-denominated short-term debt securities that, at the time of purchase, are rated by one or more rating agencies in the highest short-term rating category or, if not rated, are determined by the subadviser to be of equivalent quality.

The fund may invest in all types of money market instruments, including bank obligations, commercial paper and asset-backed securities, structured investments, repurchase agreements and other short-term debt securities. These instruments may be issued or guaranteed by all types of issuers, including U.S. and foreign banks and other private issuers, the U.S. government or any of its agencies or instrumentalities, U.S. states and municipalities, or foreign governments. These securities may pay interest at fixed, floating or adjustable rates, or may be issued at a discount. The fund may invest without limit in bank obligations, such as certificates of deposit, fixed time deposits and bankers’ acceptances. The fund generally limits its investments in foreign securities to U.S. dollar denominated obligations of issuers, including banks and foreign governments, located in the major industrialized countries, although with respect to bank obligations, the branches of the banks issuing the obligations may be located in The Bahamas or the Cayman Islands.

As a money market fund, the fund tries to maintain a share price of $1.00, and must follow strict rules as to the credit quality, liquidity, diversification and maturity of its investments. Where required by these rules, the fund’s subadviser or Board of Trustees (the “Board”) will decide whether a security should be held or sold in the event of credit downgrades or certain other events occurring after purchase.

Certain risks

An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund.

Additionally, you should be aware that a very small number of money market funds in other fund complexes have, in the past, “broken the buck,” which means that investors did not receive $1.00 per share for their investment in those funds, and any money market fund may do so in the future. You should also be aware that the fund’s manager and its affiliates are under no obligation to provide financial support to the fund or take other measures to ensure that you receive $1.00 per share for your investment in the fund. You should not invest in the fund with the expectation that any such action will be taken.

There is no assurance that the fund will meet its investment objective.

The fund could underperform other short-term debt instruments or money market funds, or you could lose money, as a result of risks such as:

Market and interest rate risk. There may be changes in interest rates, lack of liquidity or other disruptions in the bond markets or other adverse market events and conditions. The financial crisis that began in 2008 has caused a significant decline in the value and liquidity of many securities of issuers worldwide. In response to the crisis, the U.S. and other governments and the Federal Reserve and certain foreign central banks have taken steps to support financial markets. The withdrawal of this support, failure of efforts in response to the crisis, or investor perception that these efforts are not succeeding could negatively affect financial markets generally as well as the value and liquidity of certain securities. In addition, policy and legislative changes in the United States and in other countries are changing many aspects of financial regulation. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time.

Credit risk. An issuer or obligor of a security held by the fund or a counterparty to a financial contract with the fund may default or its credit may be downgraded, or the value of assets underlying a security may decline.

Yield risk. The amount of income received by the fund will go up or down depending on day-to-day variations in short-term interest rates, and when interest rates are very low the fund’s expenses could absorb all or a significant portion of the fund’s income. If interest rates increase, the fund’s yield may not increase proportionately. For example, the fund’s manager may discontinue any temporary voluntary fee limitation or recoup amounts previously waived and/or reimbursed. In addition, the recent adoption of more stringent regulations governing the management of money market funds could have a negative effect on the fund’s yield.

Risk of increase in expenses. Your actual costs of investing in the fund may be higher than the expenses shown in “Annual fund operating expenses” for a variety of reasons. For example, expense ratios may be higher than those shown if average net assets are lower than estimated, or if a fee limitation is changed or terminated.

Structured securities risk. The payment and credit qualities of structured securities derive from their underlying assets, and they may behave in ways not anticipated by the fund, or they may not receive tax, accounting or regulatory treatment anticipated by the fund.

Risks associated with concentration in the banking industry. The fund may invest a significant portion of its assets in obligations that are issued or backed by U.S. and non-U.S. banks, and thus will be more susceptible to negative events affecting the worldwide banking industry.

Foreign investments risk. The fund’s investments in securities of foreign issuers or issuers with significant exposure to foreign markets involve additional risk. Foreign countries in which the fund may invest may have markets that are less liquid, less regulated and more volatile than U.S. markets. The value of the fund’s investments may decline because of factors affecting the particular issuer as well as foreign markets and issuers generally, such as unfavorable government actions, and political or financial instability. Lack of information may also affect the value of these securities.

Prepayment or call risk. Many issuers have a right to prepay their securities. If interest rates fall, an issuer may exercise this right. If this happens, the fund will be forced to reinvest prepayment proceeds at a time when yields on securities available in the market are lower than the yield on the prepaid security.

Extension risk. If interest rates rise, repayments of fixed income securities may occur more slowly than anticipated by the market. This may drive the prices of these securities down because their interest rates are lower than the current interest rate and they remain outstanding longer.

Portfolio selection risk. The value of your investment may decrease if the subadviser’s judgment about the quality, relative yield or value of, or market trends affecting, a particular security or sector, or about interest rates generally, is incorrect.

Redemption risk. The fund may experience heavy redemptions, particularly during periods of declining or illiquid markets, that could cause the fund to liquidate its assets at inopportune times or at a loss or depressed value and that could affect the fund’s ability to maintain a $1.00 share price. In addition, the fund may suspend redemptions when permitted by applicable regulations.

These risks are discussed in more detail later in this Prospectus or in the statement of additional information (“SAI”).

Performance

The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Institutional Shares (formerly Class O shares), a class of the fund that is invested in the same portfolio of securities as Investor Shares. The table shows the average annual total returns of Institutional Shares. No performance information is presented for Investor Shares because there were no Investor Shares outstanding during the calendar years shown. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated performance information available at the fund’s website, http://www.leggmason.com/individualinvestors/products/mutual-funds/annualized_performance (select share class), or by calling the fund at 1-877-721-1926 or 1-203-703-6002.

The fund’s past performance is not necessarily an indication of how the fund will perform in the future.

Total returns (%)

Calendar Years ended December 31
Best quarter
(12/31/2006): 1.32

Worst quarter
(09/30/2011): 0.03

The year-to-date return as of the most recent calendar quarter, which ended 09/30/2012, was 0.15

Average annual total returns (for periods ended December 31, 2011) (%)

Average Annual Total Returns	1 year	5 years	Since Inception	Inception date
Investor Western Asset Institutional Cash Reserves Institutional Shares	0.17%	1.83%	2.17%	Oct. 02, 2002

[1] "Other expenses" for Investor Shares are estimated for the current fiscal year. Actual expenses may differ from estimates.

XML

Document and Entity Information	12 Months Ended
	Dec. 28, 2012
Risk/Return:
Document Type	Other
Document Period End Date	Aug. 31, 2012
Registrant Name	LEGG MASON PARTNERS INSTITUTIONAL TRUST
Central Index Key	0000889512
Amendment Flag	false
Document Creation Date	Jan. 02, 2013
Document Effective Date	Jan. 02, 2013
Prospectus Date	Dec. 28, 2012