<SUBMISSION>
<ACCESSION-NUMBER>0000920148-03-000106
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030403
<FILING-DATE>20030505
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>LABORATORY CORP OF AMERICA HOLDINGS
<CIK>0000920148
<ASSIGNED-SIC>8071
<IRS-NUMBER>133757370
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>358 S MAIN ST
<CITY>BURLINGTON
<STATE>NC
<ZIP>27215
<PHONE>3362291127
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>358 S MAIN ST
<CITY>BURLINGTON
<STATE>NC
<ZIP>27215
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>NATIONAL HEALTH LABORATORIES HOLDINGS INC
<DATE-CHANGED>19940314
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>ELINGBURG WESLEY R
<CIK>0001168584
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>001-11353
<FILM-NUMBER>03682241
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>430 S SPRING STREET
<CITY>BURLINGTON
<STATE>NC
<ZIP>27215
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4/A</documentType>

    <periodOfReport>2003-04-03</periodOfReport>

    <dateOfOriginalSubmission>2003-04-07</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000920148</issuerCik>
        <issuerName>LABORATORY CORP OF AMERICA HOLDINGS</issuerName>
        <issuerTradingSymbol>LH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001168584</rptOwnerCik>
            <rptOwnerName>ELINGBURG WESLEY R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, CFO, and Treasurer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
            <footnoteId id="F1"/>
        </securityTitle>
        <transactionDate>
            <value>2003-04-03</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>S</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>2493</value>
                <footnoteId id="F2"/>
            </transactionShares>
            <transactionValue>
                <value>30</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>189183.3177</value>
                <footnoteId id="F3"/>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">Pursuant to a plan in compliance with Rule 10b5-1 under the Securities Exchange Act of 1934.</footnote>
        <footnote id="F2">Originally reported by Mr. Elingburg's broker as 2,494 shares sold.</footnote>
        <footnote id="F3">Amount shown reflects a 2-for-1 stock split effective on May 10, 2002.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Bradford T. Smith, Attorney-in-Fact for Wesley R. Elingburg</signatureName>
        <signatureDate>2003-05-02</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
