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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 vxBx0nJCANzLYH3zvdYPVA==

<SEC-DOCUMENT>0000920148-04-000101.txt : 20040505
<SEC-HEADER>0000920148-04-000101.hdr.sgml : 20040505
<ACCEPTANCE-DATETIME>20040505155049
ACCESSION NUMBER:		0000920148-04-000101
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040503
FILED AS OF DATE:		20040505

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MITTELSTAEDT ROBERT E JR
		CENTRAL INDEX KEY:			0001200847

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11353
		FILM NUMBER:		04781546

	BUSINESS ADDRESS:	
		STREET 1:		C/O LAB CORP
		STREET 2:		430 S SPRING ST
		CITY:			BURLINGTON
		STATE:			NC
		ZIP:			27215
		BUSINESS PHONE:		3364365066

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LABORATORY CORP OF AMERICA HOLDINGS
		CENTRAL INDEX KEY:			0000920148
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MEDICAL LABORATORIES [8071]
		IRS NUMBER:				133757370
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		358 S MAIN ST
		CITY:			BURLINGTON
		STATE:			NC
		ZIP:			27215
		BUSINESS PHONE:		3362291127

	MAIL ADDRESS:	
		STREET 1:		358 S MAIN ST
		CITY:			BURLINGTON
		STATE:			NC
		ZIP:			27215

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NATIONAL HEALTH LABORATORIES HOLDINGS INC
		DATE OF NAME CHANGE:	19940314
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001200847</rptOwnerCik>
            <rptOwnerName>MITTELSTAEDT ROBERT E JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>41</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40.39</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10442</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Stock award represents half the monthly Director retainer pursuant to the Laboratory Corporation of America Holdings 1995 Stock Plan for Non-Employee Directors.</footnote>
        <footnote id="F2">Amount shown reflects a 2-for-1 stock split effective on May 10, 2002.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Bradford T. Smith, Attorney-in-Fact for Robert E. Mittelstaedt</signatureName>
        <signatureDate>2004-05-05</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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