Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
SHEFFIELD SCOTT D
   2. Issuer Name and Ticker or Trading Symbol
PIONEER NATURAL RESOURCES CO [PXD] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chairman of the Board and CEO
(Last)
(First)
(Middle)
5205 NORTH OCONNOR BLVD, SUITE 200		 3. Date of Earliest Transaction (Month/Day/Year)
02/13/2009
(Street)

IRVING, TX 75039		 4. If Amendment, Date Original Filed(Month/Day/Year)
02/18/2009		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock               447,196 D  
Common Stock               22,135 (1) I 401(k)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Phantom Stock (2)               (3)   (3) Common Stock 37,827   37,827 I Retirement Savings Plan

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SHEFFIELD SCOTT D
5205 NORTH OCONNOR BLVD
SUITE 200
IRVING, TX 75039		   X     Chairman of the Board and CEO  

Signatures

 Mark H. Kleinman, Attorney-in-Fact for Scott D. Sheffield   07/30/2009
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Consists of shares beneficially owned as a result of reporting person's ownership of units in the Pioneer Natural Rsources USA, Inc. 401(k) Plan.
(2) Each share of phantom stock represents the right to receive one share of PXD common stock or the cash value thereof.
(3) This amendment is being filed for the purpose of amending this footnote 3 in its entirety to read as follows: 7,327 of the shares of phantom stock held following the reported transactions are payable in cash following the termination of the reporting person's employment with PXD, and the reporting person may transfer such shares of his phantom stock account into an alternative investment account at any time. The retirement plan investment reported herein and giving rise to the beneficial ownership of the remaining 30,500 shares of phantom stock is irrevocable and can not be reallocated or diversified; the portion of the plan assets that reflect this investment can only be distributed in shares of PXD common stock (at the time or times that the reporting person has elected under the plan).

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