-----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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 tAKM4ekde/3eKQldhPurRw==

<SEC-DOCUMENT>0001082554-08-000062.txt : 20080605
<SEC-HEADER>0001082554-08-000062.hdr.sgml : 20080605
<ACCEPTANCE-DATETIME>20080605155309
ACCESSION NUMBER:		0001082554-08-000062
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080603
FILED AS OF DATE:		20080605
DATE AS OF CHANGE:		20080605

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNITED THERAPEUTICS CORP
		CENTRAL INDEX KEY:			0001082554
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				521984749
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1110 SPRING ST
		CITY:			SILVER SPRING
		STATE:			MD
		ZIP:			20910
		BUSINESS PHONE:		3016089292

	MAIL ADDRESS:	
		STREET 1:		1110 SPRING ST
		CITY:			SILVER SPRING
		STATE:			MD
		ZIP:			20910

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Ferrari John Maxim
		CENTRAL INDEX KEY:			0001370940

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26301
		FILM NUMBER:		08883016

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		301-608-9292

	MAIL ADDRESS:	
		STREET 1:		1110 SPRING STREET
		CITY:			SILVER SPRING
		STATE:			MD
		ZIP:			20910
</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>2008-06-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001082554</issuerCik>
        <issuerName>UNITED THERAPEUTICS CORP</issuerName>
        <issuerTradingSymbol>UTHR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001370940</rptOwnerCik>
            <rptOwnerName>Ferrari John Maxim</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1110 SPRING STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SILVER SPRING</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20910</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Share Tracking Award</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>94.06</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-06-03</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2008-06-03</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>48375</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-06-03</value>
            </exerciseDate>
            <expirationDate>
                <value>2018-06-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>48375</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48375</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These non-dilutive share tracking awards vest in one-third increments on each of June 3, 2009, June 3, 2010, and June 3, 2011, and settle in cash only.</footnote>
        <footnote id="F2">These share tracking awards replace the same number of stock options previously granted to the reporting person on April 1, 2008, contingent upon shareholder approval of the company's 2008 Equity Incentive Plan. Such contingent options were canceled because shareholder approval was not obtained.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Paul Mahon under Power of Attorney</signatureName>
        <signatureDate>2008-06-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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