SecProbe.io

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	March 29, 2005

VIA FACSIMILE and U.S. Mail

Mr. Richard P. Dealy
Executive Vice President and Chief Financial Officer
Pioneer Natural Resources Company
5205 N. O`Connor Blvd.  Suite 900
Irving, TX  75039

Re:    Pioneer Natural Resources Company
Form 10-K, Filed February 22, 2005
File No.1-13245

Dear Mr. Dealy:

      We have reviewed your filing and have the following
engineering
comments.  Where comments ask for supplemental information, please
provide us with that information within 10 business days of the
date
of this letter.  Comply with the remaining comments in your future
filings.  If you disagree with any of these comments, we will
consider your explanation as to why our comment is inapplicable or
a
revision is unnecessary.  Please be as detailed as necessary in
your
explanation.  In some of our comments, we may ask you to provide
us
with supplemental information so we may better understand your
disclosure.  After reviewing this information, we may or may not
raise additional comments.

	Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your filing.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on any other
aspect
of our review.  Feel free to call us at the telephone numbers
listed
at the end of this letter.

2004 10-K for the year ended December 31, 2004

Business, page 5

	Evergreen Merger, page 5

1. We note your reference to Evergreen`s Raton Basin coal bed
methane
reserves.  Supplementally, tell us the methodology you used to
estimate your proved CBM reserves here.  As a minimum, address:
Gas production rate criteria for attributing proved reserves to
newly
drilled exploration locations;
Criteria for use of inclining production projections;
Criteria for use of declining production projections;
Criteria for use of volumetric method and volumetric parameters
used,
particularly drainage area;
Methodology for attribution of proved undeveloped reserves;
Sources of original gas-in-place information, particularly whether
derived from desorption data.

Risks Associated with Business Activities, page 11

   Operation of natural gas processing plants, page 12

2. We note your gas plant operations discussed here.  Please amend
your future documents to disclose separately any proved NGL
reserves
you may have claimed through gas plant ownership.

International operations, page 14

3. Here and elsewhere (page 106) you discuss the application of
the
"economic interest method" for the attribution of proved reserves
under "production sharing arrangements" with foreign governments.
Amend your future documents to disclose the countries and the
proved
reserves subject to such production sharing arrangements.

Item 2  Properties, page 14

4. You indicate that Netherland, Sewell and Associates audited
your
year-end 2004 major properties` proved reserves.  In future
filings,
explain how NSAI "audits" your reserves and include the degree of
agreement, in aggregate, between your proved reserve figures and
those estimated by NSAI.  Disclose the portion of your total
reserves
included in the audit.

5. We note your statement here that the standardized measure is
calculated with oil and gas spot prices "prevailing as of the date
of
computation".  This seems contradictory to the use of year-end
prices
and costs in the estimation of proved reserves and the computation
of
the standardized measure as required by Financial Accounting
Standard
69.  Please affirm to us that you have complied with this
requirement.

Proved Reserves, page 15

6. Here and elsewhere, your disclosed U.S. proved reserves
comprise ~
84% of your total worldwide reserves.  In part, Instruction 3 to
Item
102 of Regulation S-K requires "In the case of an extractive
enterprise, material information shall be given as to production,
reserves, locations, development and the nature of the
registrant`s
interest.  If individual properties are of major significance to
an
industry segment:  A. More detailed information concerning these
matters shall be furnished."  Disclose - as a minimum - the annual
production, proved developed and total proved oil and gas reserves
for each of your major U.S. properties.

Argentine commodity prices, page 38

7. Supplementally, illustrate to us how you incorporated the
Argentine export tax into your year-end 2004 proved reserves and
standardized measure.

Production costs, page 40

8. Supplementally, tell us how oil and gas transportation costs
are
incorporated in your historical and projected - in your proved
reserve estimates and standardized measure - production costs
and/or
period end product prices.  Be advised that in our view,
transportation costs should be reflected in either the prices you
realize or the costs you incur.

Reserve Quantity Information, page 107

9. Rule 4-10(a)(4) of Regulation S-X provides that proved
undeveloped
oil and gas reserves may be attributed to locations not offsetting
productive units only "where it can be demonstrated with certainty
that there is continuity of production from the existing
productive
formation (emphasis added)."  Supplementally, submit to us the
engineering and geologic justification for any PUD reserves you
have
claimed which are not in legal, technically justified locations
offsetting (adjacent to) productive wells.  Otherwise, either
affirm
to us that none of your claimed PUD reserves are attributed to
such
locations or delete such volumes from your disclosed proved
reserves.

10. We note the 2004 reserve review and revisions that you
describe
in Exhibit I of your supplemental response.  Supplementally,
explain
why you did not apply similar revisions to the Harrier reserves.

11. Remove from your proved reserves, any quantities you have
claimed
that are:

In undrilled fault blocks;

Below the lowest known - penetrated and assessed - structural
occurrence of hydrocarbons.

12. Our review of your supplemental Exhibit A indicates that you
may
have included helium in your disclosed proved reserve estimates
and
associated standardized measure.  Paragraphs 10 and 30 of
Financial
Accounting Standard 69 prescribe that only hydrocarbon volumes and
their estimated future revenues be disclosed.  Remove from your
proved reserves any such helium volumes.

Standardized Measure of Discounted Future Net Cash Flows, page 109

13. We note your footnote (a) reference to asset retirement
obligations (ARO) here.  Address whether your proved undeveloped
reserve estimates include consideration of ARO on an individual
property basis.  Be advised we object to the attribution of proved
undeveloped reserves to individual properties whose future
estimated
production and development costs - including asset retirement
obligations - result in negative estimated future net income.
Remove
any such volumes that do not meet this requirement.

Closing Comments

      As appropriate, please amend your future documents in
response
to these comments.  You may wish to provide us with marked copies
of
the documents to expedite our review.  Please furnish a cover
letter
that keys your responses to our comments and provides any
requested
supplemental information.  Detailed cover letters greatly
facilitate
our review.  Please understand that we may have additional
comments
after reviewing your document(s) and responses to our comments.

      Please direct questions regarding engineering issues and
related disclosures to Ronald Winfrey at (202) 942-1778.  In his
absence, please contact the undersigned at (202) 942-1870.

							Sincerely,

							H. Roger Schwall
							Assistant Director

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Pioneer Natural Resources Company
March 29, 2005
page 4

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549-0405

         DIVISION OF
CORPORATION FINANCE

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