<SUBMISSION>
<ACCESSION-NUMBER>0000920148-03-000186
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20031113
<FILING-DATE>20031117
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>ELINGBURG WESLEY R
<CIK>0001168584
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-11353
<FILM-NUMBER>031006982
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>430 S SPRING STREET
<CITY>BURLINGTON
<STATE>NC
<ZIP>27215
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<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>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-11-13</periodOfReport>


    <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>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, CFO, and Treasurer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-11-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>35.43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>174359.8738</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Amount shown reflects a 2-for-1 stock split effective on May 10, 2002.  Includes 196.5561 shares acquired on June 30, 2003 under the Laboratory Corporation of America Holdings 1997 Employee Stock Purchase Plan.  Also includes mathematical corrections to prior filings made for transaction dates of May 2, 2003 and April 7, 2003.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>/s/ Bradford T. Smith, Attorney-in-Fact for Wesley R. Elingburg</signatureName>
        <signatureDate>2003-11-17</signatureDate>
    </ownerSignature>

</ownershipDocument>

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