-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 30WVuX7IS2Ay+zjOgTzXMg==

<SEC-DOCUMENT>0000704051-08-000117.txt : 20080723
<SEC-HEADER>0000704051-08-000117.hdr.sgml : 20080723
<ACCEPTANCE-DATETIME>20080723173056
ACCESSION NUMBER:		0000704051-08-000117
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080722
FILED AS OF DATE:		20080723
DATE AS OF CHANGE:		20080723

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LEGG MASON INC
		CENTRAL INDEX KEY:			0000704051
		STANDARD INDUSTRIAL CLASSIFICATION:	INVESTMENT ADVICE [6282]
		IRS NUMBER:				521200960
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		100 LIGHT ST
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202-1476
		BUSINESS PHONE:		4105390000

	MAIL ADDRESS:	
		STREET 1:		100 LIGHT ST
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202-1476

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ADAMS HAROLD L
		CENTRAL INDEX KEY:			0001195577

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08529
		FILM NUMBER:		08966509

	BUSINESS ADDRESS:	
		STREET 1:		1601 THE TERRACES
		STREET 2:		.
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21209
		BUSINESS PHONE:		410-537-6000

	MAIL ADDRESS:	
		STREET 1:		1601 THE TERRACES
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21209
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-07-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000704051</issuerCik>
        <issuerName>LEGG MASON INC</issuerName>
        <issuerTradingSymbol>LM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001195577</rptOwnerCik>
            <rptOwnerName>ADAMS HAROLD L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1601 THE TERRACES</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21209</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2008-07-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2175</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52552</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Common Stock granted pursuant to and under the conditions of the Legg Mason, Inc. Non-Employee Director Equity Plan, as amended.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Erin L. Clark, Attorney-in-fact for Harold L. Adams</signatureName>
        <signatureDate>2008-07-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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