-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 3aKs+z8njgO3UpXXFqc+pg==

<SEC-DOCUMENT>0000920148-04-000095.txt : 20040423
<SEC-HEADER>0000920148-04-000095.hdr.sgml : 20040423
<ACCEPTANCE-DATETIME>20040423153310
ACCESSION NUMBER:		0000920148-04-000095
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040421
FILED AS OF DATE:		20040423

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LAI GOLDMAN MYLA
		CENTRAL INDEX KEY:			0001168581

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11353
		FILM NUMBER:		04751015

	BUSINESS ADDRESS:	
		STREET 1:		430 S SPRING STREET
		CITY:			BURLINGTON
		STATE:			NC
		ZIP:			27215

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>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001168581</rptOwnerCik>
            <rptOwnerName>LAI GOLDMAN MYLA</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, Chief Scientific Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2004-04-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.46</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60842.644</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2004-04-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52592.644</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Options</value>
                <footnoteId id="F1"/>
                <footnoteId id="F4"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>24.46</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-04-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.46</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-02-19</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-02-19</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33960</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to a plan in accordance with Rule 10b5-1 under the Securities Exchange act of 1934.</footnote>
        <footnote id="F2">Amount shown reflects a 2-for-1 stock split effective on May 10, 2002.</footnote>
        <footnote id="F3">Includes 2,000 shares of Common Stock held in Dr. Lai-Goldman's daughter's name.  Dr. Lai-Goldman disclaims beneficial ownership of these shares.</footnote>
        <footnote id="F4">Common Stock purchase option granted under the Laboratory Corporation of America Holdings 2000 Stock Incentive Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Bradford T. Smith, Attorney-in-Fact for Myla Lai-Goldman</signatureName>
        <signatureDate>2004-04-23</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----