<SUBMISSION>
<ACCESSION-NUMBER>0001179110-07-009933
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20070510
<FILING-DATE>20070514
<DATE-OF-FILING-DATE-CHANGE>20070514
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>LIBERTY MEDIA CORP
<CIK>0001355096
<ASSIGNED-SIC>4841
<IRS-NUMBER>841288730
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>12300 LIBERTY BOULEVARD
<CITY>ENGLEWOOD
<STATE>CO
<ZIP>80112
<PHONE>7208755400
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>12300 LIBERTY BOULEVARD
<CITY>ENGLEWOOD
<STATE>CO
<ZIP>80112
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>Liberty Media Holding CORP
<DATE-CHANGED>20060303
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>ROMRELL LARRY E
<CIK>0001120556
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-51990
<FILM-NUMBER>07845343
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O LIBERTY MEDIA CORP
<STREET2>9197 SOUTH PEORIA STREET
<CITY>ENGLEWOOD
<STATE>CO
<ZIP>80112
<PHONE>8585999786
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>900 N SEWARD STREET
<CITY>HOLLYWOOD
<STATE>CA
<ZIP>90038
</MAIL-ADDRESS>
</REPORTING-OWNER>
<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>2007-05-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001355096</issuerCik>
        <issuerName>LIBERTY MEDIA CORP</issuerName>
        <issuerTradingSymbol>LCAP; LINT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001120556</rptOwnerCik>
            <rptOwnerName>ROMRELL LARRY E</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></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>116.17</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-05-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1310</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-05-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Series A Liberty Capital Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1310</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1310</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>24.80</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-05-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5710</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-05-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Series A Liberty Interactive Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5710</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5710</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The stock option will vest in full on the date of the first annual stockholders meeting of the Issuer after the date of the grant, subject to the early vesting provisions of the applicable award agreement.</footnote>
    </footnotes>

    <remarks>The trading symbols for the Issuer's Series A and Series B Liberty Capital Common Stock are LCAPA and LCAPB, respectively, and for the Issuer's Series A and Series B Liberty Interactive Common Stock are LINTA and LINTB, respectively.</remarks>

    <ownerSignature>
        <signatureName>/s/ Larry E. Romrell</signatureName>
        <signatureDate>2007-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
