-----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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 2Fk2qeyOD3gLSA+38xpWBg==

<SEC-DOCUMENT>0001246360-10-000209.txt : 20100113
<SEC-HEADER>0001246360-10-000209.hdr.sgml : 20100113
<ACCEPTANCE-DATETIME>20100113164900
ACCESSION NUMBER:		0001246360-10-000209
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100106
FILED AS OF DATE:		20100113
DATE AS OF CHANGE:		20100113

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PIONEER NATURAL RESOURCES CO
		CENTRAL INDEX KEY:			0001038357
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				752702753
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1206

	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:			SHEFFIELD SCOTT D
		CENTRAL INDEX KEY:			0001034316

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13245
		FILM NUMBER:		10525525

	MAIL ADDRESS:	
		STREET 1:		5205 NORTH OCONNOR BLVD
		STREET 2:		SUITE 900
		CITY:			IRVING
		STATE:			TX
		ZIP:			75039
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-06</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0001038357</issuerCik>
        <issuerName>PIONEER NATURAL RESOURCES CO</issuerName>
        <issuerTradingSymbol>PXD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001034316</rptOwnerCik>
            <rptOwnerName>SHEFFIELD SCOTT D</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>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22177</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-06</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2010-01-11</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7737</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>51</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>588936</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Consists of shares beneficially owned as a result of reporting person's ownership of units in the Pioneer Natural Resources USA, Inc. 401(k) Plan</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Mark H. Kleinman, Attorney-in-Fact</signatureName>
        <signatureDate>2010-01-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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