-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Bayp5CtrfL2oqmEmdNWfySVfxudmJbjivb6Gq1reZdBuoPRSNOcHfaY6c2D2SE6h
 NOhA1gDUwiHDJn7r8unQBg==

<SEC-DOCUMENT>0001179110-05-013366.txt : 20050701
<SEC-HEADER>0001179110-05-013366.hdr.sgml : 20050701
<ACCEPTANCE-DATETIME>20050701114336
ACCESSION NUMBER:		0001179110-05-013366
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050630
FILED AS OF DATE:		20050701
DATE AS OF CHANGE:		20050701

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROBISON M LAVOY
		CENTRAL INDEX KEY:			0001246361

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16615
		FILM NUMBER:		05931164

	MAIL ADDRESS:	
		STREET 1:		1001 GREEN OAKS DR
		CITY:			GREENWOOD VILLAGE
		STATE:			CO
		ZIP:			80121

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LIBERTY MEDIA CORP /DE/
		CENTRAL INDEX KEY:			0001082114
		STANDARD INDUSTRIAL CLASSIFICATION:	CABLE & OTHER PAY TELEVISION SERVICES [4841]
		IRS NUMBER:				841288730
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		12300 LIBERTY BLVD.
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112
		BUSINESS PHONE:		7208755400

	MAIL ADDRESS:	
		STREET 1:		12300 LIBERTY BLVD.
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-06-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001082114</issuerCik>
        <issuerName>LIBERTY MEDIA CORP /DE/</issuerName>
        <issuerTradingSymbol>L; LMC.B</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001246361</rptOwnerCik>
            <rptOwnerName>ROBISON M LAVOY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12300 LIBERTY BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80112</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Series A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1226</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6014</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares of Series A common stock were received by the reporting person in payment of his director fees, which equaled $12,500, for the quarter ended June 30, 2005, in accordance with the terms of the Liberty Media Corporation 2002 Nonemployee Director Incentive Plan.  The number of shares was determined based upon the closing market price of the Series A common stock on June 30, 2005, which was $10.19 per share, with cash distributed in lieu of fractional shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ M. LaVoy Robison</signatureName>
        <signatureDate>2005-07-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----