As filed with the U.S. Securities and Exchange Commission on April 6, 2007

Securities Act File No. 33-43446

Investment Company Act File No. 811-6444

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 x

Pre-Effective Amendment No.     

Post-Effective Amendment No. 67

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 x

Amendment No. 67

(Check appropriate box or boxes.)

Legg Mason Partners Investment Trust*

(Exact Name of Registrant as Specified in Charter)

125 Broad Street, New York, New York	10004
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s Telephone Number, including Area Code (800) 451-2010

Robert I. Frenkel

Legg Mason Partners Investment Trust

300 First Stamford Place

Stamford, Connecticut

(Name and Address of Agent for Service)

COPY TO:

Burton M. Leibert, Esq.

Willkie Farr & Gallagher LLP

787 Seventh Avenue

New York, New York 10019

Continuous

(Approximate Date of Proposed Offering)

It is proposed that this filing will become effective on April 16, 2007 pursuant to paragraph (b) of Rule 485 under the Securities Act of 1933, as amended. This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

* This filing relates solely to shares of the Trust’s series Legg Mason Partners S&P 500 Index Fund

Explanatory Note

Part A (the Prospectus) and Part B (the Statement of Additional Information) filed by the Registrant in Post-Effective Amendment No. 64 to the Registration Statement on Form N-1A under the Securities Act of 1933, as amended (File No. 33-43446) and Amendment No. 64 to the Registration Statement on Form N-1A under the Investment Company Act of 1940, as amended (File No. 811-6444) pursuant to Rule 485(a) on February 9, 2007 (Accession No. 0001193125-07-025370) are incorporated herein by reference. This filing is being made pursuant to Rule 485(b) under the Securities Act of 1933, as amended, to extend the effectiveness of the Registration Statement until April 16, 2007.

PART C

OTHER INFORMATION

Item 23. Exhibits

Unless otherwise noted, all references are to the Registrant’s initial registration statement on Form N-1A (the “Registration Statement”) as filed with the Securities and Exchange Commission (“SEC”) on October 21, 1991 (File Nos. 33-43446 and 811-6444).

(a)(1) Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post Effective Amendment No. 18 filed on March 30, 1998.

(2) Amendment No. 1 to the First Amended and Restated Master Trust Agreement dated June 1, 1998 is incorporated herein by reference to Post-Effective Amendment No. 20 filed on June 26, 1998.

(3) Amendment No. 2 to the First Amended and Restated Master Trust Agreement dated October 16, 1998 is incorporated herein by reference to Post-Effective Amendment No. 21 filed on November 12, 1998.

(4) Amendment No. 3 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 29 filed on August 16, 2000.

(5) Amendment No. 4 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 30 filed on August 16, 2000 (“Post-Effective Amendment No. 30”).

(6) Amendment No. 5 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 30.

(7) Amendment No. 6 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 30.

(8) Amendment No. 7 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 39 filed on March 26, 2002 (“Post-Effective Amendment No. 39”).

(9) Amendment No. 8 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 39.

(10) Amendment No. 9 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 41 filed on July 19, 2002.

(11) Amendment No. 10 to the First Amended and Restated Master Trust Agreement dated February 28, 1998 is incorporated herein by reference to Post-Effective Amendment No. 46 filed on March 30, 2003 (“Post-Effective Amendment No. 46”).

(12) Amendment No. 13 to First Amended and Restated Master Trust Agreement dated April 7, 2006 is incorporated herein by reference to Post-Effective Amendment No. 58 filed on April 28, 2006 (“Post-Effective Amendment No. 58”).

(13) Certificate of Amendment effective November 17, 2006 is incorporated herein by reference to Post-Effective Amendment No. 60 filed on November 30, 2006 (“Post-Effective Amendment No. 60”).

(b) Amended and Restated By-laws of the Registrant are incorporated herein by reference to Post-Effective Amendment No. 46.

(c) The Registrant’s form of stock certificate for Legg Mason Partners Large Cap Growth Fund is incorporated herein by reference to Post-Effective Amendment No. 17 filed on February 20, 1998.

(d)(1) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners Large Cap Growth Fund, and Legg Mason Partners Fund Advisor, LLC (“LMPFA”) dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 59 filed on September 8, 2006 (“Post-Effective Amendment No. 59”).

(2) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners Classic Values Fund, and LMPFA dated July 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63 filed on January 17, 2007 (“Post-Effective Amendment No. 63”).

(3) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners Mid Cap Core Fund, and LMPFA dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(4) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners Intermediate Maturity California Municipals Fund, and LMPFA dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(5) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners Intermediate Maturity New York Municipals Fund, and LMPFA dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(6) Form of Subadvisory Agreement between LMPFA and ClearBridge Advisors, LLC (“ClearBridge”) (formerly known as CAM North America, LLC), regarding Legg Mason Partners Large Cap Growth Fund, dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 59.

(7) Form of Subadvisory Agreement between LMPFA and Olstein & Associates, L.P. (“Olstein”), regarding Legg Mason Partners Classic Values Fund, dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(8) Form of Subadvisory Agreement between LMPFA and ClearBridge, regarding Legg Mason Partners Mid Cap Core Fund, dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(9) Form of Subadvisory Agreement between LMPFA and Western Asset Management Company (“WAM”), regarding Legg Mason Partners Intermediate Maturity California Municipals Fund, dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(10) Form of Subadivosry Agreement between LMPFA and WAM, regarding Legg Mason Partners Intermediate Maturity New York Municipals Fund, dated August 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 63.

(11) Form of Management Agreement between the Registrant, on behalf of Legg Mason Partners S&P 500 Index Fund, and LMPFA dated October 19, 2006 is incorporated herein by reference to Post-Effective Amendment No. 64.

(12) Form of Subadvisory Agreement between LMPFA and Batterymarch Financial Management, Inc. (“Batterymarch”), regarding Legg Mason Partners S&P 500 Index Fund, dated October 19, 2006 is is incorporated herein by reference to Post-Effective Amendment No. 64.

(e)(1) Form of Distribution Agreement with Citigroup Global Markets, Inc. (“CGMI”) is incorporated by reference to Post-Effective Amendment No. 30.

(2) Form of Distribution Agreement with PFS Distributors, Inc. (“PFS”) is incorporated by reference to Post-Effective Amendment No. 30.

(3) Form of Amendment to the Distribution Agreement with Citigroup Global Markets, Inc. (“CGMI”), dated as of December 1, 2005, is incorporated herein by reference to Post-Effective Amendment No. 56 filed on January 27, 2006 (“Post-Effective Amendment No. 56”).

(4) Form of Amendment of Distribution Agreement and Assumption of Duties and Responsibilities, among the Registrant, PFS Distributors, Inc. and PFS Investments, Inc. (“PFS”), dated as of December 1, 2005, is incorporated herein by reference to Post-Effective Amendment No. 56.

(5) Form of Distribution Agreement with Legg Mason Investor Services, LLC (“LMIS”) dated as of December 1, 2005 is incorporated herein by reference to Post-Effective Amendment No. 57 filed on March 30, 2006 (“Post-Effective Amendment No. 57”).

(6) Form of Letter Agreement amending Exhibit A of the Distribution Agreement between the Registrant and CGMI to be filed by amendment.

(7) Form of Letter Agreement amending Exhibit A of the Distribution Agreement between the Registrant and PFS to be filed by amendment.

(8) Form of Letter Agreement amending Exhibit A of the Distribution Agreement between the Registrant and LMIS to be filed by amendment.

(f)(1) Emeritus Retirement Plan relating to certain funds, established effective as of January 1, 2007, is incorporated herein by reference to Post-Effective Amendment No. 60.

(2) Amended and Restated Trustee Retirement Plan relating to certain funds dated as of January 1, 2005 (the “General Retirement Plan”), is incorporated herein by reference to Post-Effective Amendment No. 61 filed on January 8, 2007 (“Post-Effective Amendment No. 61”).

(3) Legg Mason Investment Series (f/k/a Smith Barney Investment Series) Amended and Restated Trustees Retirement Plan dated as of January 1, 2005, is incorporated herein by reference to Post-Effective Amendment No. 61.

(4) Amendment to the General Retirement Plan and the Legg Mason Partners Investment Series Amended and Restated Trustees Retirement Plan is incorporated herein by reference to Post-Effective Amendment No. 61.

(5) Amended and Restated Emeritus Retirement Plan relating to certain funds, established effective as of January 1, 2007, is incorporated herein by reference to Post-Effective Amendment No. 61.

(g) Form of Custodian Services Agreement between the Registrant and State Street Bank and Trust Company dated as of January 1, 2006 is incorporated herein by reference to Post-Effective Amendment No. 56.

(h)(1) Transfer Agency and Services Agreement dated January 1, 2006 between the Registrant and PFPC Inc. (“PFPC”) is incorporated herein by reference to Post-Effective Amendment No. 56.

(2) Form of License Agreement between the Registrant Legg Mason Properties, Inc. is incorporated herein by reference to Post-Effective Amendment No. 58.

(3) License Agreement between the Registrant and Citigroup Inc. dated December 1, 2005 is incorporated herein by reference to Post-Effective Amendment No. 58.

(4) Form of Fee Waiver and Expense Reimbursement Agreement is incorporated herein by reference to Post-Effective Amendment No. 60.

(i)(1) Opinion of Counsel regarding legality of shares being registered is incorporated herein by reference to Pre-Effective Amendment No. 1 filed on December 6, 1991 (“Pre-Effective Amendment No. 1”).

(2) Legal Counsel’s consent is incorporated herein by reference to Post-Effective Amendment No. 24 filed on March 30, 1999.

(3) Opinion of Counsel regarding legality of Class FI and Class R Shares being registered is incorporated herein by reference to Post-Effective Amendment No. 60.

(j)(1) Consent of Independent Registered Public Accounting Firm to be filed by amendment.

(2) Power of Attorney dated April 12, 2006 is incorporated herein by reference to Post-Effective Amendment No. 58.

(k) Not Applicable.

(l) Purchase Agreement between the Registrant and Shearson Lehman Brothers Inc. is incorporated herein by reference to Pre-Effective Amendment No. 1.

(m)(1) Amended Shareholder Services and Distribution Plan pursuant to Rule 12b-1 between the Registrant, on behalf of Legg Mason Partners Intermediate Maturity California Municipals Fund, Legg Mason Partners Intermediate Maturity New York Municipals Fund, Legg Mason Partners Classic Values Fund, Legg Mason Partners Large Capitalization Growth Fund, Legg Mason Partners Mid Cap Core Fund, Legg Mason Partners S&P 500 Index Fund, and LMIS (relating to Class A, B, C and I shares), dated December 1, 2005, is incorporated herein by reference to Post-Effective Amendment No. 57.

(2) Amended Shareholder Services and Distribution Plan between the Registrant, on behalf of Legg Mason Partners Large Capitalization Growth Fund, and LMIS (relating to Class FI and R shares), dated August 1, 2006, is incorporated herein by reference to Post-Effective Amendment No. 60.

(3) Amended Shareholder Services and Distribution Plan between the Registrant and LMIS to be filed by amendment.

(n)(1) Amended Rule 18f-3(d) Multiple Class Plan of the Registrant is incorporated herein by reference to Post-Effective Amendment No. 56.

(2) Amended Rule 18f-3(d) Multiple Class Plan of the Registrant is incorporated herein by reference to Post-Effective Amendment No. 60.

(3) Amended and Restated Rule 18f-3(d) Multiple Class Plan to be filed by amendment.

(o) Not Applicable

(p)(1) Code of Ethics of Citigroup Asset Management—North America and Certain Registered Investment Companies, as amended September 13, 2005 (adopted by LMPFA and ClearBridge), is incorporated herein by reference to Post-Effective Amendment No. 56.

(2) Code of Ethics of LMIS dated December 1, 2005 is incorporated herein by reference to Post-Effective Amendment No. 56.

(3) Code of Ethics of CGMI to be filed by amendment.

(4) Code of Ethics of PFS to be filed by amendment.

(5) Code of Ethics of Barrett Associates, Inc. (“Barrett”) dated December 15, 2005 is incorporated herein by reference to Post-Effective Amendment No. 61.

(6) Code of Ethics of Legg Mason International Equities Limited (“LMIE”) is incorporated herein by reference to Post-Effective Amendment No. 61.

(7) Code of Ethics of Batterymarch Financial Management, Inc. (“Batterymarch”) dated February 1,2005 is incorporated herein by reference to Post-Effective Amendment No. 61.

(8) Code of Ethics of Brandywine Global Investment Management, LLC (“Brandywine”) to be filed by amendment.

(9) Code of Ethics of Causeway Capital Management LLC (“Causeway”) to be filed by amendment.

(10) Code of Ethics of WAM dated as of February, 2005, is incorporated herein by reference to Post-Effective Amendment No. 62 filed on January 10, 2007 (“Post-Effective Amendment No. 62”).

(11) Code of Ethics of Legg Mason Investment Counsel, LLC (“LMIC”) is incorporated herein by reference to Post-Effective Amendment No. 62.

(12) Code of Ethics of Olstein to be filed by amendment.

Item 24. Persons Controlled by or under Common Control with Registrant

Not Applicable.

Item 25. Indemnification

The response to this item is incorporated herein by reference to Pre-Effective Amendment No. 1.

The directors and officers of the Registrant and the personnel of the Registrant’s manager are insured under an errors and omissions liability insurance policy. The Registrant and its officers are also insured under the fidelity bond required by Rule 17g-1 under the Investment Company Act of 1940.

Reference is hereby made to (a) Section 4 of the Distribution Agreement between the Registrant and Citigroup Global Markets Inc. (the “CGMI Distribution Agreement”), incorporated by reference herein; (b) paragraph 7 of the Amendment to the CGMI Distribution Agreement incorporated by reference herein; (c) Section 4 of the Distribution Agreement between the Registrant and PFS Distributors, Inc. (the “PFS Distribution Agreement”), incorporated by reference herein; (d) paragraph 7 of the Amendment to the PFS Distribution Agreement incorporated by reference herein; (e) paragraph 9 of the Distribution Agreement between the Registrant and Legg Mason Investor Services, LLC, incorporated by reference herein.

Item 26. Business and Other Connections of Investment Adviser

Investment Adviser — Legg Mason Partners Fund Advisor, LLC (“LMPFA”)

LMPFA was formed in 2006 under the laws of the State of Delaware as a limited liability company. LMPFA is a direct wholly-owned subsidiary of Legg Mason, Inc. (“Legg Mason”).

LMPFA is registered as an investment adviser under the Investment Advisers Act of 1940, as amended. The list required by this Item 26 of officers and directors of LMPFA together with information as to any other business, profession, vocation or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated by reference to Schedules A and D of Form ADV filed by LMPFA pursuant to the Investment Advisers Act of 1940, as amended (SEC File No. 801-66785).

Subadviser — Barrett Associates, Inc. (“Barrett”)

Barrett was organized under the laws of the State of New York as a corporation. Barrett is a wholly-owned subsidiary of Legg Mason.

Barrett is registered as an investment adviser under the Investment Advisers Act of 1940, as amended. The list required by this Item 26 of officers and directors of Barrett together with information as to any other business, profession, vocation or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated by reference to Schedules A and D of Form ADV filed by Barrett pursuant to the Investment Advisers Act of 1940, as amended (SEC File No. 801- 831).

Subadviser—Batterymarch Financial Management, Inc. (“Batterymarch”)

Batterymarch was organized under the laws of the State of Maryland as a corporation. Batterymarch is an indirect wholly-owned subsidiary of Legg Mason.

Batterymarch is registered as an investment adviser under the Investment Advisers Act of 1940, as amended. The list required by this Item 26 of officers and directors of Batterymarch together with information as to any other business, profession, vocation or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated by reference to Schedules A and D of Form ADV filed by Batterymarch pursuant to the Investment Advisers Act of 1940, as amended (SEC File No. 801- 48035).

Subadvisor —Legg Mason International Equities Limited (“LMIE”)

The list required by this Item 26 of officers and directors of LMIE, together with information as to any other business, profession, vocation or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated by reference to Schedules A and D of Form ADV filed by LMIE pursuant to the Advisers Act (SEC File No. 801-57655).

Subadviser — Western Asset Management Company (“WAM”) is an investment adviser registered with the SEC under the Advisers Act. The following is a list of other substantial business activities in which directors, officers or partners of WAM have been engaged as director, officer, employee, partner, or trustee.

Peter L. Bain	Director, WAM
	Director, LMFM
	Manager, Brandywine
	Senior Executive Vice President, Legg Mason, Inc.
	Director, Nova Scotia
	Vice President and Director, BMML
	Director, LMCM
	Director, Bartlett
	Director, Berkshire
	Director, LM Funding
	Director, LM Properties
	Director, LMRG
	Director, LM Tower
	Director, PCM I
	Director, PCM II
	Manager, Royce
	Director, Western Asset Management Company Limited

James W. Hirschmann III	Director, WAM
	Director, Western Asset Management Company Limited
D. Daniel Fleet	President and CEO, WAM
Gavin L. James	Director of Global Client Services, WAM
	Senior Executive Officer, Western Asset Management Company Limited
Gregory McShea	General Counsel and Secretary, WAM
	General Counsel and Secretary, Western Asset Management Company Limited

WAM is located at 385 East Colorado Boulevard, Pasadena, CA 91101.

Item 27. Principal Underwriters

(a) CGMI, a distributor of the Registrant, is the distributor for each series of the registrants listed: Legg Mason Partners Trust II, CitiFunds Trust I, Legg Mason Partners Funds Trust, Variable Annuity Portfolios, CitiFunds Premium Trust, CitiFunds Institutional Trust, CitiFunds Trust III, Legg Mason Partners Lifestyle Series, Inc., Smith Barney Multiple Discipline Trust, Legg Mason Partners Investment Series, Consulting Group Capital Markets Funds, High Income Opportunity Fund Inc., Intermediate Muni Fund, Inc., Legg Mason Partners Small Cap Core Fund, Inc., Legg Mason Partners Investment Trust, LMP Real Estate Income Fund Inc., Managed High Income Portfolio Inc., Managed Municipals Portfolio Inc., Municipal High Income Fund Inc., Citigroup Investments Corporate Loan Fund Inc., Zenix Income Fund Inc., Legg Mason Partners Capital Fund, Inc., Legg Mason Partners Investors Value Fund, Inc., Legg Mason Partners Equity Fund, Inc., Western Asset Funds II, Inc., Legg Mason Partners Series Funds, Inc., Legg Mason Partners Variable Portfolios I, Inc., Barrett Opportunity Fund, Inc. (prior to 12/1/06, Salomon Brothers Opportunity Fund Inc), Western Asset 2008 Worldwide Dollar Government Term Trust Inc., Western Asset High Income Fund Inc., Western Asset High Income Fund II Inc., Western Asset Emerging Markets Income Fund Inc., Western Asset Emerging Markets Income Fund II Inc., Western Asset Emerging Markets Floating Rate Fund Inc., Western Asset Global High Income Fund Inc., Western Asset Emerging Markets Debt Fund Inc., LMP Capital and Income Fund, Inc., Western Asset Inflation Management Fund Inc., Western Asset Variable Rate Strategic Fund, Inc., Western Asset Global Partners Income Fund Inc., Western Asset Municipal Partners Fund Inc., Western Asset Municipal Partners Fund II Inc., Legg Mason Partners Variable Portfolio II, Legg Mason Partners Adjustable Rate Income Fund, Legg Mason Partners Aggressive Growth Fund, Inc., Legg Mason Partners Appreciation Fund, Inc., Legg Mason Partners Arizona Municipals Fund, Inc., Legg Mason Partners California Municipals Fund, Inc., Legg Mason Partners Equity Funds, Legg Mason Partners Fundamental Value Fund, Inc., Legg Mason Partners Funds, Inc., Legg Mason Partners Income Funds, Smith Barney Institutional Cash Management Fund, Inc., Legg Mason Partners Investment Funds, Inc., Legg Mason Partners Core Plus Bond Fund, Inc., Legg Mason Partners Managed Municipals Fund, Inc., Legg Mason Partners Massachusetts Municipals Fund, Smith Barney Money Funds, Inc., Legg Mason Partners Municipal Funds, Smith Barney Municipal Money Market Fund, Inc., Legg Mason Partners New Jersey Municipals Fund, Inc., Legg Mason Partners Sector Series, Inc., Legg Mason Partners Oregon Municipals Fund, Legg Mason Partners World Funds, Inc., and various series of unit investment trusts.

LMIS, a distributor of the Registrant is also a distributor of the following funds: Legg Mason Partners Trust II, CitiFunds Trust I, Legg Mason Partners Funds Trust, Variable Annuity Portfolios, CitiFunds Premium Trust, CitiFunds Institutional Trust, CitiFunds Trust III, Legg Mason Partners Lifestyle Series, Inc., Smith Barney Multiple Discipline Trust, Legg Mason Partners Investment Series, Consulting Group Capital Markets Funds, High Income Opportunity Fund Inc., Intermediate Muni Fund, Inc., Legg Mason Partners Small Cap Core Fund, Inc., Legg Mason Partners Investment Trust, LMP Real Estate Income Fund Inc., Managed High Income Portfolio Inc., Managed Municipals Portfolio Inc., Municipal High Income Fund Inc., Citigroup Investments Corporate Loan Fund Inc., Zenix Income Fund Inc., Legg Mason Partners Capital Fund, Inc., Legg Mason Partners Investors Value Fund, Inc., Legg Mason Partners Equity Fund, Inc., Western Asset Funds II, Inc., Legg Mason Partners Series Funds, Inc., Legg Mason Partners Variable Portfolios I, Inc., Barrett Opportunity Fund, Inc. (prior to 12/1/06, Salomon Brothers Opportunity Fund Inc), Western Asset 2008 Worldwide Government Term Trust Inc., Western Asset High Income Fund Inc., Western Asset High Income Fund II Inc., Western Asset Emerging Markets Income Fund Inc., Western Asset Emerging Markets Income Fund II Inc., Western Asset Emerging Markets Floating Rate Fund Inc., Western Asset Global High Income Fund Inc., Western Asset Emerging Markets Debt Fund Inc., LMP Capital and Income Fund Inc., Western Asset Inflation Management Fund Inc., Western Asset Variable Rate Strategic Fund Inc., Western Asset Global Partners Income Fund Inc., Western Asset Municipal Partners Fund Inc., Western Asset Municipal Partners Fund II Inc., Legg Mason Partners Variable Portfolios II, Legg Mason Partners Adjustable Rate Income Fund, Legg Mason Partners Aggressive Growth Fund, Inc., Legg Mason Partners Appreciation Fund, Inc., Legg Mason Partners California Municipals Fund, Inc.,

Legg Mason Partners Equity Funds, Legg Mason Partners Fundamental Value Fund, Inc., Legg Mason Partners Funds, Inc., Legg Mason Partners Income Funds, Smith Barney Institutional Cash Management Fund, Inc., Legg Mason Partners Investment Funds, Inc., Legg Mason Partners Core Plus Bond Fund, Inc., Legg Mason Partners Managed Municipals Fund, Inc., Legg Mason Partners Massachusetts Municipal Fund, Smith Barney Money Funds, Inc., Legg Mason Partners Municipal Funds, Smith Barney Municipal Money Market Fund, Inc., Legg Mason Partners New Jersey Municipals Fund, Inc., Legg Mason Partners Oregon Municipals Fund, Legg Mason Partners World Funds, Inc., Legg Mason Partners Sector Series, Inc., Travelers Series Fund Inc., Legg Mason Cash Reserve Trust, Inc., Legg Mason Charles Street Trust, Inc., Legg Mason Global Trust, Inc., Legg Mason Growth Trust, Inc., Legg Mason Income Trust, Inc., Legg Mason Investment Trust, Inc., Legg Mason Investors Trust, Inc., Legg Mason Light Street Trust, Inc., Legg Mason Special Investment Trust, Inc., Legg Mason Tax Exempt Trust, Inc., Legg Mason Tax-Free Income Fund, Legg Mason Value Trust, Inc., Western Asset Funds, Inc.

LMIS is the placement agent for Institutional Enhanced Portfolio, Prime Cash Reserves Portfolio, U.S. Treasury Reserves Portfolio, Tax Free Reserves Portfolio and Liquid Reserves Portfolio.

PFS Investments Inc. (“PFS”), a distributor of the Registrant, is also the distributor for certain series of the registrants listed: Legg Mason Partners Trust II, Legg Mason Partners Lifestyle Series, Inc., Legg Mason Partners Investment Series, Legg Mason Partners Investment Trust, Legg Mason Partners Aggressive Growth Fund, Inc., Legg Mason Partners Appreciation Fund, Inc., Legg Mason Partners California Municipals Fund, Inc., Legg Mason Partners Equity Funds, Legg Mason Partners Fundamental Value Fund, Inc., Legg Mason Partners Funds, Inc., Legg Mason Partners Income Funds, Legg Mason Partners Investment Funds, Inc., Legg Mason Partners Managed Municipals Fund, Inc., Smith Barney Money Funds Inc. and Legg Mason Partners Sector Series, Inc.

(b) The information required by this Item 27 with respect to each director, officer and partner of CGMI is incorporated by reference to Schedule A of Form BD filed by CGMI pursuant to the Securities Exchange Act of 1934 (SEC File No. 8-8177):

The information required by this Item 27 with respect to each director and officer of LMIS is listed below:

Timothy C. Scheve – Managing Director

Mark R. Fetting – Managing Director

D. Stuart Bowers – Vice President

W. Talbot Daley – Vice President

Thomas J. Hirschmann – Vice President

Joseph M. Furey – General Counsel and Chief Compliance Officer

Ronald Holinsky – Counsel

Robert E. Patterson – Counsel

Theresa M. Silberzahn – Chief Financial Officer

Elisabeth F. Craig – AML Compliance Officer and Director of Continuing Education

All Addresses are 100 Light Street, Baltimore, Maryland 21202.

The information required by this Item 27 with respect to each director, officer and partner of PFS is incorporated by reference to Schedule A of Form BD filed by PFS pursuant to the Securities Exchange Act of 1934 (SEC File No. 8-37352).

(c) Not applicable.

Item 28. Location of Accounts and Records

With respect to the Registrant:

(1) Legg Mason Partners Investment Trust

125 Broad Street

New York, New York 10004

With respect to the Registrant’s Investment Manager:

(2) c/o Legg Mason Partners Fund Advisor, LLC

399 Park Avenue

New York, NY 10022

With respect to the Registrant’s Subadvisers:

(3) c/o Legg Mason International Entities Limited

399 Park Avenue

New York, NY 10022

(4) Barrett Associates, Inc.

90 Park Avenue

34th Floor

New York, NY 10016

(5) Batterymarch Financial Management, Inc.

John Hancock Tower

200 Clarendon Street

Boston, MA 02116

(6) c/o ClearBridge Advisors, LLC

399 Park Avenue

New York, NY 10022

(7) c/o Western Asset Management Company

399 Park Avenue

New York, NY 10022

(8) c/o Legg Mason Investment Counsel, LLC

399 Park Avenue

New York, NY 10022

(9) c/o Causeway Capital Management LLC

399 Park Avenue

New York, NY 10022

(10) Olstein & Associates, L.P.

105 Corporate Park Drive

White Plains, NY 10604

With respect to the Registrant’s Custodian:

(11) State Street Bank & Trust Company

One Lincoln Street

Boston, MA 02111

With respect to the Registrant’s Transfer Agent:

(12) PFPC Inc.

P.O. Box 9699

Providence, Rhode Island 02940-9699

With respect to the Registrant’s Distributors:

(13) Citigroup Global Markets Inc.

388 Greenwich Street

New York, New York 10013

(14) Legg Mason Investor Services, LLC

100 Light Street

Baltimore, MD 21202

(15) PFS Investments, Inc.

3120 Breckinridge Blvd

Duluth, GA 30099-0062

Item 29. Management Services

Not applicable.

Item 30. Undertakings

Not applicable.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended (the “Securities Act”), and the Investment Company Act of 1940, as amended, the Registrant, LEGG MASON PARTNERS INVESTMENT TRUST, certifies that it meets all requirements for effectiveness of this Post-Effective Amendment to the Registration Statement pursuant to Rule 485(b) under the Securities Act and has duly caused this Post-Effective Amendment to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, State of New York on this 6th day of April, 2007.

LEGG MASON PARTNERS INVESTMENT TRUST, on behalf of its series

Legg Mason Partners S&P 500 Index Fund

By:	/s/ R. Jay Gerken
	R. Jay Gerken Chairman of the Board (Chief Executive Officer)

WITNESS our hands on the date set forth below.

Pursuant to the requirements of the Securities Act, this Post-Effective Amendment has been signed below by the following persons in the capacities indicated below on April 6, 2007.

Signature	Title
/s/ R. Jay Gerken R. Jay Gerken	President, Principal Executive Officer and Trustee
/s/ Kaprel Ozsolak Kaprel Ozsolak	Treasurer and Chief Financial Officer
/s/ Dwight B. Crane* Dwight B. Crane	Trustee
/s/ Burt N. Dorsett* Burt N. Dorsett	Trustee
/s/ Stephen E. Kaufman* Stephen E. Kaufman	Trustee
/s/ Cornelius C. Rose, Jr.* Cornelius C. Rose, Jr.	Trustee

*By:	/s/ R. Jay Gerken
	R. Jay Gerken

* Attorney-in-Fact, pursuant to Power of Attorney dated April 12, 2006.

INDEX TO EXHIBITS

Exhibit No.	Description of Exhibit
	Not Applicable.