EXHIBIT 4.1

                          THIRD SUPPLEMENTAL INDENTURE

     THIS THIRD  SUPPLEMENTAL  INDENTURE  dated as of  September  30, 2004 (this
"Supplemental  Indenture"),  is  entered  into  by  and  among  Pioneer  Natural
Resources Company, a Delaware corporation ("Pioneer"),  Pioneer Debt Sub, LLC, a
Texas limited  liability  company and a wholly-owned  subsidiary of Pioneer (the
"Company"),  and Wachovia  Bank,  National  Association,  the successor to First
Union National Bank, a national banking association, as trustee (the "Trustee").
Capitalized  terms used herein and not  otherwise  defined have the meanings set
forth in the Indenture referred to below.

                                    RECITALS

     A. Pursuant to the terms of that certain Agreement and Plan of Merger dated
as of September 29, 2004, by and among the Company, Pioneer BC Asset Sub, LLC, a
Texas limited  liability  company and a  wholly-owned  subsidiary of the Company
("Asset Sub"), and Pioneer Evergreen Properties,  LLC, a Texas limited liability
company and a wholly-owned  subsidiary of Pioneer  ("Merger Sub"),  the Company,
Asset Sub and Merger Sub have merged into each other, with the Company and Asset
Sub as the surviving entities (the "Merger").

     B.  Pursuant to the terms of the Merger and the Texas law, the  obligations
of the Merger Sub under the Indenture and the Securities  were allocated to, and
became liabilities of the Company in the Merger.

     B. Pursuant to Article VII of that certain  Indenture  dated as of December
18,  2001,  by and among  Merger Sub,  Pioneer  and the  Trustee (as  heretofore
amended and supplemented, the "Indenture"), upon consummation of the Merger, the
Company  shall  expressly  assume,  by  supplemental  indenture,   executed  and
delivered to the Trustee all  obligations  of Merger Sub under the Indenture and
the 4.75% Senior Convertible Notes due 2021 issued thereunder (the "Securities")
and the Company will succeed to, and be substituted  for, and may exercise every
right and power of Merger Sub under the Indenture and the Securities.

     C. In accordance with Section 11.1(a) of the Indenture, the Company and the
Trustee are  authorized  to execute and deliver this  Supplemental  Indenture to
amend  the  Indenture  to  provide  for the  assumption  by the  Company  of the
obligations of Merger Sub under the Indenture and the Securities  without notice
to or the consent of any Securityholder.

     D. Each of the Company and Pioneer desires and has requested the Trustee to
join with it in entering  into this  Supplemental  Indenture  for the purpose of
amending  the  Indenture  to provide  for the  assumption  by the Company of the
obligations of Merger Sub under the Indenture and the Securities.

     E. The Company and Pioneer have duly  authorized the execution and delivery
of this Supplemental Indenture.







                                   AGREEMENTS

     NOW,  THEREFORE,  in  consideration of the foregoing and for other good and
valuable  consideration,  the  receipt  of which  is  hereby  acknowledged,  the
Company,  Pioneer,  and the Trustee covenant and agree for the equal and ratable
benefit of the Holders of the Securities as follows:

     Section 1.  Confirmation  of  Original  Indenture.  Except as  amended  and
supplemented hereby, the Indenture is hereby ratified,  confirmed and reaffirmed
in all respects.  The Indenture and this  Supplemental  Indenture shall be read,
taken and construed as one and the same instrument.

     Section 2. Successor Company Substituted. In accordance with Article VII of
the Indenture,  upon  consummation of the Merger,  the Company shall succeed to,
and be  substituted  for, and may exercise  every right and power of, Merger Sub
under the  Securities  and the Indenture  with the same effect as if the Company
had been named therein as Merger Sub.

     Section 3. Assumption of Obligations.  Upon consummation of the Merger, the
Company hereby assumes all of the  obligations of Merger Sub under the Indenture
and the Securities with the same effect as if the Company had been named therein
as Merger Sub.

     Section 4.  Miscellaneous.

            (a) Execution of Supplemental Indenture. This Supplemental Indenture
is executed and shall be construed as an indenture supplemental to the Indenture
and, as provided in the Indenture,  this Supplemental  Indenture forms a part of
the Indenture.

            (b) NEW YORK LAW TO GOVERN.  THE  INTERNAL LAW OF  THE STATE  OF NEW
YORK SHALL  GOVERN  AND BE USED TO  CONSTRUE  THIS  SUPPLEMENTAL  INDENTURE  BUT
WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT
THAT THE  APPLICATION  OF THE LAWS OF  ANOTHER  JURISDICTION  WOULD BE  REQUIRED
THEREBY.

            (c) Counterparts.  The parties may sign any number of copies of this
Supplemental  Indenture.  Each signed copy shall be an original, but all of them
together represent the same agreement.

            (d) Effect  of  Headings.  The   Section  headings  herein  are  for
convenience only and shall not affect the construction hereof.

            (e) The Trustee.  The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals  contained  herein,  all of which
recitals are made solely by Pioneer and the Company.

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     IN WITNESS  WHEREOF,  the parties  hereto  have  caused  this  Supplemental
Indenture to be duly executed as of the date first above written.



                                       PIONEER DEBT SUB, LLC

                                       By:    /s/ Richard P. Dealy
                                              ---------------------------------
                                              Name:  Richard P. Dealy
                                              Title:  President



                                       PIONEER NATURAL RESOURCES COMPANY

                                       By:    /s/ Richard P. Dealy
                                              ---------------------------------
                                              Name:  Richard P. Dealy
                                              Title:  Vice President



                                       WACHOVIA BANK, NATIONAL ASSOCIATION,
                                         as Trustee

                                       By:    /s/ Doug Milner
                                              ---------------------------------
                                              Authorized Signatory


               Signature Page to the Third Supplemental Indenture
                        (4.75% Senior Convertible Notes)