-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 O2RnJ0UDxx2wp3EUMOhhObisaBKLponsqsubum8YkhCP9F7EWJXIhTNzqB7CgrpF
 +xnlFyERkA/f5K5HVwQUSg==

<SEC-DOCUMENT>0000704051-03-000099.txt : 20030512
<SEC-HEADER>0000704051-03-000099.hdr.sgml : 20030512
<ACCEPTANCE-DATETIME>20030512165414
ACCESSION NUMBER:		0000704051-03-000099
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030509
FILED AS OF DATE:		20030512

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LEGG MASON INC
		CENTRAL INDEX KEY:			0000704051
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		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:			MASON RAYMOND A
		CENTRAL INDEX KEY:			0001206665

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08529
		FILM NUMBER:		03693252

	BUSINESS ADDRESS:	
		STREET 1:		100 LIGHT STREET
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202
		BUSINESS PHONE:		410 539 0000

	MAIL ADDRESS:	
		STREET 1:		LEGG MASON INC
		STREET 2:		L00 LIGHT ST
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-05-09</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001206665</rptOwnerCik>
            <rptOwnerName>MASON RAYMOND A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, President &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeSecurity>
        <securityTitle>
            <value>Phantom Stock</value>
            <footnoteId id="F1"/>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>0</value>
            <footnoteId id="F2"/>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-05-09</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>A</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>39.61</value>
            </transactionShares>
            <transactionValue>
                <value>51.34</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>1988-08-08</value>
            <footnoteId id="F3"/>
        </exerciseDate>
        <expirationDate>
            <value>1988-08-08</value>
            <footnoteId id="F4"/>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>Common Stock</value>
            </underlyingSecurityTitle>
            <underlyingSecurityShares>
                <value>39.61</value>
            </underlyingSecurityShares>
        </underlyingSecurity>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>41061.69</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <footnotes>
        <footnote id="F1">Phantom Stock units acquired pursuant to the Legg Mason Wood Walker, Incorporated Deferred Compensation Phantom Stock Plan.</footnote>
        <footnote id="F2">1-for-1</footnote>
        <footnote id="F3">Phantom Stock units acquired pursuant to the Legg Mason Wood Walker, Incorporated Deferred Compensation Phantom Stock Plan do not have a specific date exercisable.</footnote>
        <footnote id="F4">Phantom Stock units acquired pursuant to the Legg Mason Wood Walker, Incorporated Deferred Compensation Phantom Stock Plan do not have an expiration date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Thomas C. Merchant, Attorney-in-Fact</signatureName>
        <signatureDate>2003-05-12</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----