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                                                                   EXHIBIT 10.34


                                                                  Execution Copy

                            FIRST AMENDING AGREEMENT

                THIS FIRST AMENDING AGREEMENT dated June 29, 1998



BETWEEN:

                      PIONEER NATURAL RESOURCES CANADA INC.

                                     - and -

                               THE LENDERS HERETO

                                     - and -

                       CANADIAN IMPERIAL BANK OF COMMERCE


PREAMBLE:

                  The parties hereto are parties to the Credit Agreement dated
as of December 18, 1997 (the "Credit Agreement") and wish to amend the Credit
Agreement to reflect changes to the credit established thereunder.

                  NOW THEREFORE in consideration of the covenants and agreements
between the parties contained in this First Amending Agreement and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as follows:

1.       INTERPRETATION

         In this First Amending Agreement, capitalized terms which are not
otherwise defined herein shall have the meaning given in the Credit Agreement.

2.       AMENDMENTS

         The Credit Agreement is hereby amended as follows:

         (a)      Section 3.12(a) is deleted and replaced with the following:

                  (a)   INTEREST AND FEES. Interest payable by the Borrower
                        under each Accommodation shall be determined in the
                        following manner:

                        (i)   each Canadian Prime Rate Loan shall bear
                              interest at a variable rate of interest per annum
                              equal to the Canadian Prime Rate;



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                        (ii)    each U.S. Base Rate Loan shall bear interest at
                                a variable rate per annum equal to the U.S. Base
                                Rate;

                        (iii)   each Alternate Base Rate Loan shall bear
                                interest at a variable rate of interest per
                                annum equal to the Alternate Base Rate;

                        (iv)    each LIBOR Based Loan shall bear interest at a
                                rate per annum equal to the sum of: (i) LIBOR,
                                plus (ii) the applicable Commitment Utilization
                                Margin, plus (iii) the applicable margin based
                                on the Applicable Rating Level as indicated in
                                the table below;

                        (v)     each Canadian Eurodollar Loan shall bear
                                interest at a rate per annum equal to the sum
                                of: (i) the Canadian Eurodollar Rate, plus (ii)
                                the applicable Commitment Utilization Margin,
                                plus (iii) the applicable margin based on the
                                Applicable Rating Level as indicated on the
                                table below; and

                        (vi)    for each Bankers' Acceptance, the stamping fee
                                payable by the Borrower on the acceptance
                                thereof by the Canadian Resident Lenders shall
                                be based on the sum of: (i) the applicable
                                Commitment Utilization Margin, plus (ii) the
                                applicable margin based on the Applicable Rating
                                Level as indicated in the table below.



- --------------------------------------------------------------------------------
Applicable Rating Level         I        II        III        IV          V
- --------------------------------------------------------------------------------
                                                          
Stamping fee on Bankers'        18       20        23         36         45
Acceptances and margins
  on LIBOR Based
  Loans/Canadian
Eurodollar Loans (Basis
      Points)
- --------------------------------------------------------------------------------


           (b)  Section 13.1 is amended with the addition of the following as
                Section 13.1(r):

                (r)     YEAR 2000 COMPLIANCE

                        (i)   In this Section 13.1(r):



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                                "YEAR 2000 PROBLEM" means the risk that computer
                                applications used by the Borrower or any of its
                                Subsidiaries (or its suppliers and vendors) may
                                be unable to recognize and perform properly
                                date- sensitive functions involving certain
                                dates prior to, and any date after, December 31,
                                1999; and

                                "YEAR 2000 COMPLIANT" means that all computer
                                applications will on a timely basis be able to
                                perform properly date-sensitive functions for
                                all dates before and after January 1, 2000.

                        (ii)    The Borrower has: (i) initiated a review
                                and assessment of all areas within its and each
                                of its Subsidiaries' business and operations
                                (including those affected by suppliers and
                                vendors) that could be adversely affected by the
                                Year 2000 Problem, (ii) developed a plan and
                                time line for addressing the Year 2000 Problem
                                on a timely basis, and (iii) to date,
                                implemented that plan in accordance with that
                                time table. The Borrower reasonably believes
                                that all computer applications (including those
                                of its suppliers and vendors) that are material
                                to its or any of its Subsidiaries' business and
                                operations will be Year 2000 Compliant, except
                                to the extent that a failure to do so could not
                                reasonably be expected to have a Material
                                Adverse Effect.

           (c)  Section 14.1 is amended with the addition of the following as
                14.1(n):

                (n)     YEAR 2000 COMPLIANCE. The Borrower will promptly notify
                        the Agent in the event the Borrower discovers or
                        determines that any computer application (including
                        those of its suppliers and vendors) that is material to
                        its or any of its Subsidiaries' business and operations
                        will not be Year 2000 Compliant on a timely basis,
                        except to the extent that such failure could not
                        reasonably be expected to have a Material Adverse
                        Effect.

           (d)  Schedule "A" is amended with the addition of the following
                definitions in appropriate alphabetical order:

                "Commitment Utilization" means, for any period, the ratio of:
                (i) the Outstandings to (ii) the Commitment Amount, provided
                that for purposes of determining the Commitment Utilization
                Margin for the period ending June 30, 1999, the Commitment
                Utilization is deemed to be ">.50".



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                  "COMMITMENT UTILIZATION LEVEL" means the level set forth below
                  that corresponds to the lowest of the ratings issued from time
                  to time by Moody's and S&P, as applicable, for the Parent's
                  senior unsecured long-term debt:



================================================================================
                      Moody's                  S&P
- --------------------------------------------------------------------------------
                                                 
Level A            Baa3 or better        BBB- or better
Level B            Less than Baa3        Less than BBB-
================================================================================



                  For example, if the Moody's rating is Ba1 and the S&P rating
                  is BBB, Level B shall apply. For purposes of the foregoing,
                  (i) if ratings for the Parent's senior unsecured long-term
                  debt shall not be available from S&P or Moody's, Level B shall
                  be deemed applicable; and (ii) if any of the Rating Agencies
                  shall change its ratings nomenclature prior to the date all
                  Obligations have been paid and the Commitments cancelled, the
                  Parent and the Lenders shall negotiate in good faith to amend
                  the reference to specific ratings in this definition to
                  reflect such change, and pending such amendment, if an
                  appropriate Commitment Utilization Level is otherwise not
                  determinable based upon the foregoing grid, the last
                  Commitment Utilization Level in effect at the time of such
                  change shall continue to apply.

                  "Commitment Utilization Margin" means, on any date, the number
                  of Basis Points per annum set forth below based on the
                  Commitment Utilization Level on such date:





- --------------------------------------------------------------------------------
                               Commitment Utilization Margin
- --------------------------------------------------------------------------------
   Commitment                  Commitment Utilization           Commitment
Utilization Level              is "< or equal to .50"      Utilization is ">.50"
- --------------------------------------------------------------------------------
                                                         
    Level A                            0 b.p.                     5.0 b.p
- --------------------------------------------------------------------------------
    Level B                            0 b.p.                    10.0 b.p
- --------------------------------------------------------------------------------



                "Year 2000 Compliant" has the meaning attributed to it in
                Section 13.1(r) of the Agreement.

                "Year 2000 Problem" has the meaning attributed to it in Section
                13.1(r) of the Agreement.

3. Representations and Warranties. To confirm each Lender's understanding
concerning the Borrower and its businesses, properties and obligations, and to
induce the Agent and each Lender to enter into this First Amending Agreement,
the Borrower hereby reaffirms to the Agent and each Lender that, as of the date
hereof, its representations and warranties contained in Section




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13.1 of the Credit Agreement (as amended by this First Amending Agreement) and
in the Documents to which it is a party (except to the extent such
representations and warranties relate solely to an earlier date) are true and
correct and additionally represents and warrants as follows:

        (a)     The execution and delivery of this First Amending Agreement and
                the performance by the Borrower and the Restricted Subsidiaries
                of their respective obligations under this First Amending
                Agreement, the Credit Agreement and the other Documents, as
                amended hereby, are within the Borrower's or such Restrictive
                Subsidiaries' corporate powers, have been duly authorized by all
                necessary corporate action, have received all necessary
                governmental approval (if any shall be required), and do not and
                will not contravene or conflict with any provision of Law or of
                the Borrower's or such Restrictive Subsidiaries' constating
                documents or by-laws or of any Law or material agreement,
                judgment, license, order or permit applicable to or binding upon
                such Borrower or Restrictive Subsidiary.

        (b)     This First Amending Agreement and the Credit Agreement, as
                amended hereby, are, and the other Documents when fully executed
                and delivered will be, legal, valid and binding obligations of
                the Borrower and each Restrictive Subsidiary which is a party
                hereto or thereto, enforceable in accordance with their terms
                except as such enforcement may be limited by applicable
                bankruptcy, insolvency, reorganization, winding-up, moratorium
                or similar Laws relating to the enforcement of creditors' rights
                generally and by general principles of equity.


4. Conditions to Effectiveness. The effectiveness of this First Amending
Agreement is conditional upon the following:

        (a)     The Borrower shall pay, or cause the payment, to the Agent for
                the account of each Lender a non-refundable amendment fee
                determined by applying the amendment fee rate of 15 Basis Points
                to the Commitments (whether used or unused) as of the date of
                this First Amending Agreement. Such amendment fee shall be
                allocated among the Lenders based on their Pro-Rata Shares; and

        (b)     The Borrower shall deliver such other documents or items that
                the Agent may reasonably request in a form and substance
                reasonably satisfactory to the Agent.

5. Effective Date. The amendments contained herein shall be effective as of the
date of this First Amending Agreement.

6. Continuing Effect. Each of the parties hereto acknowledges and agrees that
the Credit Agreement, as amended by this First Amending Agreement, the Support
Guarantees and the Parent Guarantee each dated as of December 18, 1997 delivered
to the Agent and Lenders, shall be and continue in full force and effect and are
hereby confirmed and the rights and obligations




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of all parties thereunder shall not be affected or prejudiced in any manner
except as specifically provided for herein.

7. Counterparts. This First Amending Agreement may be executed in any number of
counterparts, each of which when executed and delivered shall be deemed to be an
original, but all of which when taken together constitute one and the same
instrument; any party may execute this First Amending Agreement by signing any
counterpart of it.

         IN WITNESS WHEREOF, the Parties have caused this First Amending
Agreement to be duly executed by their respective authorized officers as of the
day and year first above written.


                                     PIONEER NATURAL RESOURCES CANADA INC., 
                                     as Borrower

                                     By: /s/ Jane Stevenson
                                        ----------------------------------------
                                     Name:   Jane Stevenson
                                     Title:  Controller


                                     CANADIAN IMPERIAL BANK OF COMMERCE, 
                                     as Canadian Resident Lender and
                                     Administrative Agent


                                     By: /s/ David Swain
                                        ----------------------------------------
                                     Name:   David Swain
                                     Title:  Vice President

                                     By: /s/ James Chepyha
                                        ----------------------------------------
                                     Name:   James Chepyha
                                     Title:  Executive Director

                                     Address:
                                     Bankers Hall, 10th floor
                                     855-2nd Street S.W.
                                     Calgary, Alberta  T2P 4J7
                                     Fax: 403-221-5779



      This is a counterpart execution page to the First Amending Agreement
dated June 29, 1998.





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                                     THE BANK OF NOVA SCOTIA, 
                                     as Canadian Resident Lender


                                     By: /s/ Dan Belot
                                        ----------------------------------------
                                     Name:   Dan Belot
                                     Title:  Relationship Manager

                                     By: /s/ Michael Jackson
                                        ----------------------------------------
                                     Name:   Michael Jackson
                                     Title:  Vice President and Office Head

                                     Address:
                                     Corporate & Energy Banking
                                     Suite 3820, 700-2nd Street S.W.
                                     Calgary, Alberta  T2P 2N7
                                     Fax:  403-221-6497


                                     ROYAL BANK OF CANADA,
                                     as Canadian Resident Lender

                                     By: /s/ Bruce Edgelow                    
                                        ----------------------------------------
                                     Name:   Bruce Edgelow
                                     Title:  Senior Account Manager


                                     By: /s/ Lorne Gartner                    
                                        ----------------------------------------
                                     Name:   Lorne Gartner
                                     Title:  Manager

                                     Address:
                                     Oil & Gas Banking Centre
                                     335 8th Avenue S.W., 11th floor,
                                     Calgary, Alberta  T2P 1C9
                                     Fax:  403-292-3436



             This is a counterpart execution page to the First Amending
Agreement dated June 29, 1998.



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                                                                  Execution Copy

                                     THE CHASE MANHATTAN BANK OF CANADA, 
                                     as Canadian Resident Lender

                                     By: /s/ Christine Chan
                                        ----------------------------------------
                                     Name:   Christine Chan
                                     Title:  Vice President

                                     Address:
                                     1 First Canadian Place
                                     6900, 100 King Street West
                                     Toronto, Ontario  M5X  1A4
                                     Fax:  416-216-4161


                                     MORGAN GUARANTY TRUST COMPANY OF NEW YORK,
                                     as Non-resident Lender

                                     By: /s/ John Kowalczuk
                                        ----------------------------------------
                                     Name:   John Kowalczuk
                                     Title:  Vice President

                                     Address:
                                     60 Wall Street, 22nd floor
                                     New York, New York  10260
                                     Fax:  212-648-5014


                                     NATIONSBANK, N.A.,
                                     successor-by-merger to NationsBank of
                                     Texas, N.A. as Non-resident Lender

                                     By: /s/ Frank Stowers
                                        ----------------------------------------
                                     Name:   Frank Stowers
                                     Title:  Vice President

                                     Address:
                                     303 West Wall Street
                                     Midland, Texas  79701
                                     Fax:  915-685-2009



             This is a counterpart execution page to the First Amending
Agreement dated June 29, 1998.


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                                     THE TORONTO-DOMINION BANK, 
                                     as Canadian Resident Lender

                                     By: /s/ Loretta Palandri
                                        ----------------------------------------
                                     Name:   Loretta Palandri
                                     Title:  Manager, Corporate Banking

                                     Address:
                                     800 Home Oil Tower
                                     324-8th Avenue S.W.
                                     Calgary, Alberta  T2P 2Z2
                                     Fax:  403-292-2772


                                     FIRST UNION NATIONAL BANK,
                                     as Non-resident Lender

                                     By: /s/ Michael Kolosowsky
                                        ----------------------------------------
                                     Name:   Michael Kolosowsky
                                     Title:  Vice President

                                     Address:
                                     One First Union Center
                                     301 South College Street, TW-11
                                     Charlotte, North Carolina  28288-0658
                                     Fax:  704-374-6249


                                     WACHOVIA BANK, N.A., 
                                     as Non-resident Lender

                                     By: /s/ Paige Mesaros
                                        ----------------------------------------
                                     Name:   Paige Mesaros
                                     Title:  Vice President

                                     Address:
                                     191 Peachtree Street N.E.
                                     MC370, 28th floor
                                     Atlanta, Georgia  30303
                                     Fax:  404-332-6898





             This is a counterpart execution page to the First Amending
Agreement dated June 29, 1998.