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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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<SEC-DOCUMENT>0001209191-08-026148.txt : 20080429
<SEC-HEADER>0001209191-08-026148.hdr.sgml : 20080429
<ACCEPTANCE-DATETIME>20080429110915
ACCESSION NUMBER:		0001209191-08-026148
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080429
FILED AS OF DATE:		20080429
DATE AS OF CHANGE:		20080429

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Pioneer Southwest Energy Partners L.P.
		CENTRAL INDEX KEY:			0001407463
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				260388421
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5205 N. O'CONNOR BLVD., SUITE 200
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039
		BUSINESS PHONE:		(972) 444-9001

	MAIL ADDRESS:	
		STREET 1:		5205 N. O'CONNOR BLVD., SUITE 200
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PIONEER NATURAL RESOURCES CO
		CENTRAL INDEX KEY:			0001038357
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1206

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34032
		FILM NUMBER:		08783629

	BUSINESS ADDRESS:	
		STREET 1:		200 WILLIAMS SQUARE WEST
		STREET 2:		5205 N OCONNOR BLVD
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039
		BUSINESS PHONE:		9724449001

	MAIL ADDRESS:	
		STREET 1:		200 WILLIAMS SQUARE WEST
		STREET 2:		5205 N OCONNOR BLVD
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PIONEER NATURAL RESOURCES USA INC
		CENTRAL INDEX KEY:			0000846920
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34032
		FILM NUMBER:		08783630

	BUSINESS ADDRESS:	
		STREET 1:		5205 NORTH O CONNOR BOULEVARD
		STREET 2:		1400 WILLIAMS SQUARE WEST
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039
		BUSINESS PHONE:		9156834768

	MAIL ADDRESS:	
		STREET 1:		5205 NORTH OCONNOR BOULEVARD
		STREET 2:		1400 WILLIAMS SQUARE WEST
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039

	FORMER NAME:	
		FORMER CONFORMED NAME:	MESA OPERATING CO
		DATE OF NAME CHANGE:	19940113

	FORMER NAME:	
		FORMER CONFORMED NAME:	MESA OPERATING LIMITED PARNERSHIP
		DATE OF NAME CHANGE:	19940113
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc3.xml
<DESCRIPTION>FORM 3 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-04-29</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001407463</issuerCik>
        <issuerName>Pioneer Southwest Energy Partners L.P.</issuerName>
        <issuerTradingSymbol>PSE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001038357</rptOwnerCik>
            <rptOwnerName>PIONEER NATURAL RESOURCES CO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5205 N. O'CONNOR BLVD, SUITE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Indirect Owner of GP</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000846920</rptOwnerCik>
            <rptOwnerName>PIONEER NATURAL RESOURCES USA INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5205 N. O'CONNOR BLVD., SUITE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Direct Owner of GP</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>No securities beneficially owned</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This Form 3 is being filed in connection with the effectiveness of the Issuer's Registration Statement on Form S-1 (Registration No. 333-144868) initially filed with the Securities and Exchange Commission on September 13, 2007, as amended.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mark H. Kleinman, Vice President</signatureName>
        <signatureDate>2008-04-29</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Mark H. Kleinman, Vice President</signatureName>
        <signatureDate>2008-04-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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