As filed with the Securities and Exchange Commission on June 25, 2001


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM 11-K

              / x / ANNUAL REPORT PURSUANT TO SECTION 15(D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                   For the fiscal year ended December 31, 2000

                                       OR

             / / TRANSITION REPORT PURSUANT TO SECTION 15 (D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

              For the transition period from _________ to _________

                          Commission File No. 333-39249

A.    Full title of the plan and the address of the plan, if different from that
      of the issuer named below:

                 PIONEER NATURAL RESOURCES USA, INC. 401(k) PLAN


B.    Name of issuer of the securities held pursuant to the plan and the address
      of its principal executive officer:


                        Pioneer Natural Resources Company
                      5205 North O'Connor Blvd., Suite 1400
                               Irving, Texas 75039







                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN


                 Financial Statements and Supplemental Schedule

    As of December 31, 2000 and 1999 and for the year ended December 31, 2000

                       With Report of Independent Auditor





                                       2







                 PIONEER NATURAL RESOURCES USA, INC. 401(k) PLAN

                      AS OF DECEMBER 31, 2000 AND 1999 AND
                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 2000


                                Table of Contents


                                                                       Page


Report of Independent Auditor.....................................      4

Statements of Net Assets Available for Benefits as of
   December 31, 2000 and 1999.....................................      5

Statement of Changes in Net Assets Available for Benefits
   for the year ended December 31, 2000...........................      6

Notes to Financial Statements.....................................      7

Schedule H; Line 4i - Schedule of Assets (Held At End of Year)
   as of December 31, 2000........................................     11

Signatures........................................................     12

Index to Exhibits.................................................     13



                                       3










                          Report of Independent Auditor


To the Participants and the Plan Administrator
of Pioneer Natural Resources USA, Inc.
401(k) Plan:

We have audited the accompanying statements of net assets available for benefits
of Pioneer  Natural  Resources USA, Inc. 401(k) Plan as of December 31, 2000 and
1999, and the related  statement of changes in net assets available for benefits
for the year  ended  December  31,  2000.  These  financial  statements  are the
responsibility  of the Plan's  management.  Our  responsibility is to express an
opinion on these financial statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable  assurance about whether the financial  statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting  the amounts and  disclosures in the financial  statements.  An audit
also includes assessing the accounting principles used and significant estimates
made by  management,  as well as  evaluating  the  overall  financial  statement
presentation.  We believe  that our audits  provide a  reasonable  basis for our
opinion.

In our opinion,  the financial  statements  referred to above present fairly, in
all  material  respects,  the net assets  available  for benefits of the Plan at
December  31,  2000 and 1999,  and the changes in its net assets  available  for
benefits for the year ended  December 31, 2000,  in conformity  with  accounting
principles generally accepted in the United States.

Our audits were performed for the purpose of forming an opinion on the financial
statements taken as a whole. The  accompanying  supplemental  schedule of assets
(held at end of year) as of December 31, 2000,  is presented  for the purpose of
additional  analysis and is not a required part of the financial  statements but
is  supplementary  information  required by the  Department of Labor's Rules and
Regulations for Reporting and Disclosure  under the Employee  Retirement  Income
Security Act of 1974. This  supplemental  schedule is the  responsibility of the
Plan's management.  The supplemental schedule has been subjected to the auditing
procedures  applied  in our  audits  of the  financial  statements  and,  in our
opinion,  is fairly stated in all material respects in relation to the financial
statements taken as a whole.


                                              Ernst & Young LLP




Fort Worth, Texas
June 25, 2001


                                       4







                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

                 Statements of Net Assets Available for Benefits




                                                           December 31,
                                                    --------------------------
                                                        2000          1999
                                                    -----------    -----------

                                                             
Investments at fair value:
  Vanguard Primecap Fund........................    $21,148,244    $17,456,153
  Vanguard Prime Money Market Fund..............     12,394,091     13,079,816
  Vanguard 500 Index Fund.......................      9,400,834      8,798,844
  Vanguard Windsor II Fund......................      6,525,824      6,327,893
  Vanguard - ST Corporate Fund..................      3,112,481      3,468,610
  Vanguard International Growth Fund............      1,028,195        773,868
  Vanguard Total Bond Market Index Fund.........        220,638          -
  Vanguard Asset Allocation Fund................        122,262          -
  Sarofim Equity Fund...........................     12,688,210     19,943,740
  Pioneer Natural Resources Stock Fund .........      5,326,283      2,191,408
                                                     ----------     ----------

                                                     71,967,062     72,040,332

Participants' loans.............................      1,220,876      1,359,021
                                                     ----------     ----------

  Net assets available for benefits.............    $73,187,938    $73,399,353
                                                     ==========     ==========





                 See accompanying notes to financial statements.

                                       5







                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

            Statement of Changes in Net Assets Available for Benefits
                      For the year ended December 31, 2000





                                                            
Additions to net assets attributed to:
  Net investment income:
     Interest and dividend income...........................   $   3,173,510
     Net appreciation in fair value of investments..........       1,844,074
                                                                 -----------
                                                                   5,017,584

  Employee contributions....................................       2,737,596
  Rollovers.................................................          87,228
                                                                 -----------
     Total additions........................................       7,842,408
                                                                 -----------
Deductions from net assets attributed to:
  Distributions to participants.............................       8,000,618
  Fees......................................................          53,205
                                                                 -----------
     Total deductions.......................................       8,053,823
                                                                 -----------
Net decrease................................................        (211,415)

Net assets available for benefits:
  Beginning of year.........................................      73,399,353
                                                                 -----------
  End of year...............................................   $  73,187,938
                                                                ============







                 See accompanying notes to financial statements.

                                       6







                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS
                           December 31, 2000 and 1999


Note 1.       Description of Plan

       The following  brief  description of the  Pioneer Natural  Resources USA,
Inc. 401(k) Plan (the "Plan")  provides only general  information.  Participants
should refer to the Summary Plan  Description for a complete  description of the
Plan, a copy of which is available to each  participant from the Pioneer Natural
Resources USA, Inc. 401(k) Plan Committee (the "Plan  Administrator").  The Plan
is subject to the provisions of the Employee  Retirement  Income Security Act of
1974 ("ERISA").

       General

       The Plan is a  defined contribution plan  established under  the Internal
Revenue Code (the "Code")  Section 401 on January 1, 1990 covering all employees
of  Pioneer  Natural  Resources  USA,  Inc.  (the  "Employer"),  a  wholly-owned
subsidiary  of  Pioneer  Natural  Resources  Company  (the  "Company").  Regular
full-time  employees and part-time  employees are eligible to participate on the
first day of the month following their date of hire.

       Contributions

       Participants may  contribute an amount  of not less than two  percent nor
more than 12 percent of their annual salary. An Employer match is contributed in
cash to the Pioneer Natural  Resources USA, Inc. Matching Plan ("Matching Plan")
at an  amount  equal  to  200  percent  of  the  first  five  percent  of  basic
compensation contributed by a participant to the Plan.

       Participant Accounts

       Each   participant's   account  is   credited   with  the   participant's
contributions and an allocation of Plan earnings. Plan earnings are allocated to
each participant's  account by fund in proportion to their fund balance relative
to the total fund balance.

       Participants  may borrow from their  accounts a minimum of $1,000 up to a
maximum of $50,000, or 50 percent of their account's vested balances,  whichever
amount is less.  The loans  are  secured  by the  balance  in the  participant's
account.  Participant  loans bear  interest at an annual rate equal to the prime
borrowing rate at the inception of the loan plus one percent. Loan principal and
interest is paid ratably through payroll deductions.

       Investment Options

       Participants  were  able  to  allocate  their  contributions   among  the
following investment options during the Plan year ended December 31, 2000:

       o      Vanguard Prime  Money Market Fund  -  Seeks to provide high income
              and a  stable share  price of  $1 by investing in short-term, high
              quality money market instruments issued by financial institutions,
              non-financial  corporations,  the  United  States  government  and
              United States federal agencies.

       o      Vanguard - ST Corporate Fund  -  Seeks to  provide a high level of
              current  income  by  investing  in  short-term,   investment-grade
              corporate bonds with average maturities of two to three years.


                                       7






                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS
                           December 31, 2000 and 1999


Note 1.       Description of Plan (continued)

       o      Vanguard 500  Index Fund  -  Seeks to provide  long-term growth of
              capital and income from dividends by holding all of the 500 stocks
              that make  up the unmanaged  Standard & Poor's 500 Composite Stock
              Price Index,  a widely recognized benchmark of United States stock
              market performance.

       o      Vanguard  Primecap Fund  -  Seeks long-term  growth of  capital by
              investing in  stocks of companies with above-average prospects for
              continued earnings growth,  strong industry  positions and skilled
              management teams.

       o      Vanguard Windsor II Fund  -  Seeks to provide  long-term growth of
              capital  and a  reasonable  level  of  income  from  dividends  by
              investing in  a diversified group of  undervalued or  out-of-favor
              stocks  of large  capitalization companies.  The stocks  generally
              sell at prices below  the overall market average compared to their
              dividend income and future return potential.

       o      Vanguard International Growth Fund  -  Seeks to  provide long-term
              growth of  capital by  investing  in  stocks  of  companies  based
              outside the United States.  Stocks are  selected from more than 15
              countries.

       o      Vanguard Asset Allocation Fund - Seeks to maximize total return by
              investing in common stocks, bonds and money market instruments.

       o      Vanguard Total Bond Market Index Fund  -  Seeks to generate a high
              level of  interest  income by  investing in  high-credit  quality,
              corporate and treasury securities.

       o      Sarofim Equity Fund  -  Seeks to provide high growth of capital by
              investing  in a  broadly diversified portfolio of large companies.
              Income is a secondary goal.

       o      Pioneer  Natural  Resources  Stock  Fund  -  The  Pioneer  Natural
              Resources  Stock Fund is  designed to  provide long-term growth of
              capital through increases in the value  of the common stock of the
              Company.  Dividends,  if  any,  are  reinvested  to  purchase more
              shares.

       Vesting

       As is described in more detail in  "Contributions"  above,  participants'
contributions   and  Plan  earnings  are   maintained  in  the  Plan.   Employer
contributions are maintained in the Matching Plan, together with the earnings of
the Matching Plan.

       Participants  are immediately  vested  in their  voluntary  contributions
currently  being made into the Plan,  plus the  actual  Plan  earnings  thereon.
Certain  participant  account  balances  that  were  merged  into the Plan  from
predecessor plans retained the vesting schedules provided for in the predecessor
plans' documents. Vesting in the Matching Plan is based upon years of continuous
service.  A participant is fully vested in the Matching Plan after four years of
service.

                                       8








                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS
                           December 31, 2000 and 1999


Note 1.       Description of Plan (continued)

       Payments of Benefits

       If the total value of the  vested portion of the participant's account is
$5,000 or less, payment will be made in one lump sum as soon as administratively
possible.  If the total value of the vested portion of the participant's account
exceeds  $5,000,  payment  will  occur  at age  70-1/2  unless  the  participant
terminates,  retires or becomes  disabled prior to age 70-1/2 and consents to an
earlier  distribution date by filing a written request to the Plan Administrator
within  90  days  prior  to  the  date  the  participant  wishes  to  receive  a
distribution.  Except for participant accounts that have a total vested value of
$5,000 or less,  distributions to terminated,  retired or disabled  participants
will be annuities,  but may be  installments or lump sum payments if so directed
by the participant.  A participant's  beneficiary will receive the participant's
account balance in the event of a participant's death.

       Withdrawal of Benefits

       Employees may  withdraw their  vested assets  in the  Plan under  certain
hardship conditions  as defined in the  Plan agreement.  Terminated participants
may also withdraw their vested assets in the Plan.

       Plan Termination

       Although it has not expressed any intent to do so,  the  Employer has the
right  under  the  Plan to  discontinue  its  contributions  at any  time and to
terminate  the Plan  subject  to the  provisions  of ERISA.  In the event of the
Plan's termination, participants will become fully vested in their accounts.

Note 2.       Summary of Significant Accounting Policies

       Basis of Presentation

       The accompanying financial  statements have been  prepared on the accrual
basis of accounting in accordance with accounting  principles generally accepted
in the United States.  Benefit  payments made to participants  are recorded upon
distribution.

       Investment Valuation

       Investments are valued  at fair value as determined by Vanguard Fiduciary
Trust Company (the "Trustee"). Fair value is determined as follows:

       1)   Investments in  securities  traded on  national securities exchanges
            are valued at the last reported sales price on the last business day
            of the year.

       2)   Investments  in  money  market  funds  are  valued  at  cost,  which
            approximates fair value.

       3)   Participant  loans  receivable are  valued at their unpaid principal
            balance, which approximates fair value.

       4)   Investments  in the  Vanguard  Prime Money Market Fund are valued at
            cost, which approximates fair value.


                                       9






                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS
                           December 31, 2000 and 1999


Note 2.     Summary of Significant Accounting Policies (continued)

       Security Transactions and Investment Income

       Security transactions are  accounted for on a trade-date basis.  Expenses
incurred with transactions,  if any, are added to the purchase price or deducted
from the  selling  price at the time of the  transactions.  Dividend  income  is
recorded on the ex-dividend  date.  Income from other investments is recorded as
earned on an accrual basis.

Note 3.     Investments

       During 2000, the Plan's investments  (including investments bought,  sold
and held during the year) appreciated (depreciated) in fair value as follows:


                                                             
              Pioneer Natural Resources Stock Fund              $  2,966,444
              Registered Investment Companies                    ( 1,122,370)
                                                                 -----------
                                                                $  1,844,074
                                                                 ===========


Note 4.       Administrative Expenses

       Administrative  expenses  paid by the  Plan were  $53,205 during the year
ended December 31, 2000. The Employer may pay certain  expenses  incurred in the
establishment and administration of the Plan, including expenses and fees of the
Trustee,  but is not  obligated  to do so.  Any  Plan  expenses  not paid by the
Employer are paid from the Plan's earnings or account  forfeitures.  In addition
to  administrative  expenses paid by the Plan, Plan  administrative  expenses of
$50,545  and  $5,435  were  paid  from  account  forfeitures  and the  Employer,
respectively,  during 2000. Account forfeiture balances in the Plan were $74,024
and $115,052 as of December 31, 2000 and 1999, respectively.

Note 5.       Tax Status of the Plan

       The Plan  received a  determination  letter  from  the  Internal  Revenue
Service dated January 14, 1999, stating that the Plan is qualified under Section
401(a) of the Code and,  therefore,  the related trust is exempt from  taxation.
The Plan is required  to operate in  conformity  with the Code to  maintain  its
qualification.  The Plan  Administrator  believes the Plan is being  operated in
compliance with the applicable requirements of the Code and, therefore, believes
that the Plan is qualified and the related trust is tax exempt.

Note 6.       Related Party Transactions

       Certain Plan  investments are shares of  registered  investment companies
managed by Vanguard Fiduciary Trust Company. Vanguard Fiduciary Trust Company is
the Trustee as defined by the Plan and, therefore, these transactions qualify as
party-in-interest.



                                       10











                       PIONEER NATURAL RESOURCES USA, INC.
                                   401(k) PLAN

         Schedule H; Line 4i - Schedule of Assets (Held At End of Year)
                                 EIN: 75-2516853
                                Plan Number: 001

                             As of December 31, 2000

                                                               (c)
                                                         Description of
                       (b)                            investment including
                Identity of issuer,                  maturity date, rate of                 (e)
                 borrower, lessor,                  interest, collateral, par             Current
 (a)             or similar party                       or maturity value                  Value
-----    --------------------------------    ---------------------------------------    -----------

                                                                               
  *      Vanguard Fiduciary Trust Company    Vanguard Primecap Fund -
                                                  350,252 shares                        $21,148,244
  *      Vanguard Fiduciary Trust Company    Vanguard Prime Money Market Fund -
                                               12,394,091 shares                         12,394,091
  *      Vanguard Fiduciary Trust Company    Vanguard 500 Index Fund -
                                               77,145 shares                              9,400,834
  *      Vanguard Fiduciary Trust Company    Vanguard Windsor II Fund -
                                               239,920 shares                             6,525,824
  *      Vanguard Fiduciary Trust Company    Vanguard - ST Corporate Fund -
                                               292,252 shares                             3,112,481
  *      Vanguard Fiduciary Trust Company    Vanguard International Growth
                                               Fund - 54,488 shares                       1,028,195
   *     Vanguard Fiduciary Trust Company    Vanguard Total Bond Market Index -
                                                22,152 shares                               220,638
  *      Vanguard Fiduciary Trust Company    Vanguard Asset Allocation Fund  -
                                                5,165 shares                                122,262
         Fayez Sarofim & Co.                 Sarofim Equity Fund - 234,013 shares        12,688,210
  *      Pioneer Natural Resources Company   Pioneer Natural Resources Stock Fund -
                                               751,239 units                              5,326,283
  *      Participants' loans                 Interest rates range from 8.75% to 10.5%     1,220,876
                                                                                         ----------

                                                                                        $73,187,938
                                                                                         ==========
---------------------------
*Party in-interest

Note: Column (d) is not applicable since all investments are participant
      directed.



                                       11











                 PIONEER NATURAL RESOURCES USA, INC. 401(k) PLAN

                               S I G N A T U R E S


Pursuant to the requirements of the Securities Exchange Act of 1934, the Plan
Administrator has duly caused this annual report to be signed on its behalf by
the undersigned thereto duly authorized.

                                PIONEER NATURAL RESOURCES USA, INC. 401(k) PLAN

                                By:    Pioneer Natural Resources USA, Inc.
                                       401(k) Plan Committee


Date:    June 25, 2001          By:     /s/ Larry N. Paulsen
                                       -------------------------------
                                       Larry N. Paulsen
                                       Chairman


Date:    June 25, 2001          By:     /s/ Rich Dealy
                                       -------------------------------
                                       Rich Dealy


Date:    June 25, 2001          By:     /s/ John V. Peters
                                       -------------------------------
                                       John V. Peters


Date:    June 25, 2001          By:     /s/ Kevin Schepel
                                       -------------------------------
                                       Kevin Schepel


Date:    June 25, 2001          By:     /s/ David W. Simpson
                                       -------------------------------
                                       David W. Simpson


                                       12










                                INDEX TO EXHIBITS



Exhibit
Number                         Description                              Page
-------                        -----------                              ----

  23.1                         Consent of Ernst & Young LLP              14









                                       13










                                                                    EXHIBIT 23.1

                         CONSENT OF INDEPENDENT AUDITOR



We consent to the incorporation by reference in the Registration Statement (Form
S-8 No. 333-39249) pertaining to the Pioneer Natural Resources USA,  Inc. 401(k)
Plan of our report dated June 25, 2001, with respect to the financial statements
and schedule of the Pioneer Natural Resources USA, Inc. 401(k) Plan  included in
this Annual  Report on  Form 11-K as of  December 31,  2000 and 1999 and for the
year ended December 31, 2000.



                                           Ernst & Young LLP



Fort Worth, Texas
June 25, 2001


                                       14