EXHIBIT 4.2

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITARY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), NEW YORK, NEW YORK, TO
THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER,  EXCHANGE OR PAYMENT, AND
ANY  CERTIFICATE  ISSUED IS  REGISTERED  IN THE NAME OF CEDE & CO. OR SUCH OTHER
NAME AS IS REQUESTED BY AN AUTHORIZED  REPRESENTATIVE OF DTC (AND ANY PAYMENT IS
MADE TO CEDE & CO., OR TO SUCH OTHER  ENTITY AS IS  REQUESTED  BY AN  AUTHORIZED
REPRESENTATIVE  OF DTC) ANY  TRANSFER,  PLEDGE OR OTHER USE  HEREOF FOR VALUE OR
OTHERWISE  BY OR TO ANY PERSON IS  WRONGFUL  INASMUCH  AS THE  REGISTERED  OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

     TRANSFERS OF THIS GLOBAL  SECURITY  SHALL BE LIMITED TO TRANSFERS IN WHOLE,
BUT  NOT IN  PART,  TO  NOMINEES  OF  DTC  OR TO A  SUCCESSOR  THEREOF  OR  SUCH
SUCCESSOR'S  NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL  SECURITY SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE  RESTRICTIONS  SET FORTH IN THE
INDENTURE REFERRED TO ON THE REVERSE HEREOF.






                               [FACE OF SECURITY]

CUSIP NO. 723787 AF 4

No. T-01                                                            $450,000,000

                          6.875% Senior Notes due 2018

     Pioneer Natural Resources Company, a Delaware corporation,  promises to pay
to Cede & Co., or registered assigns,  the principal sum of $450,000,000 Dollars
on May 1, 2018.

     Interest Payment Dates:         May 1 and November 1
               Record Dates:         April 15 and October 15

     Additional  provisions  of this Security are set forth on the other side of
this Security.

Dated:  May 1, 2006

                                         PIONEER NATURAL RESOURCES COMPANY


                                         By: /s/ Richard P. Dealy
                                             ---------------------------------
                                             Richard P. Dealy
                                             Executive Vice President and
                                             Chief Financial Officer



                                         By: /s/ Mark H. Kleinman
                                             ----------------------------------
                                             Mark H. Kleinman
                                             Secretary



                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

     THE BANK OF NEW YORK TRUST COMPANY,  N.A., as Trustee,  certifies that this
is one of the Debt Securities, designated 6.875% Senior Notes due 2018, referred
to in the Indenture.


                                         By: /s/ John C. Stohlmann
                                             ----------------------------------
                                             Authorized Signatory


                                       2





                              [REVERSE OF SECURITY]

                          6.875% Senior Notes due 2018

 1.  Interest

     Pioneer  Natural   Resources   Company,   a  Delaware   corporation   (such
corporation,  and its  successors  and assigns under the  Indenture  hereinafter
referred to, being herein called the "Company"), promises to pay interest on the
principal amount of this Security at the rate per annum shown above. The Company
shall pay interest  semiannually on May 1 and November 1 of each year commencing
on  November  1, 2006.  Interest on the  Securities  shall  accrue from the most
recent date to which  interest  has been paid or, if no interest  has been paid,
from May 1, 2006.  Interest  shall be computed on the basis of a 360-day year of
twelve 30-day months.  The Company shall pay interest on overdue principal at 1%
per  annum in  excess  of the rate  borne by the  Securities,  and it shall  pay
interest on overdue  installments  of interest at such higher rate to the extent
lawful.

 2.  Method of Payment

     The  Company  shall  pay  interest  on  the  Securities  (except  defaulted
interest) to the Persons who are  registered  holders of Securities at the close
of business on the April 15 or October 15 next  preceding  the interest  payment
date even if Securities  are canceled after the record date and on or before the
interest  payment date.  Holders must surrender  Securities to a Paying Agent to
collect  principal  payments.  The Company  shall pay  principal and interest in
immediately  available (same day) funds in money of the United States of America
that at the time of payment is legal  tender for  payment of public and  private
debts.  However,  the Company may pay  principal  and  interest by check or wire
transfer payable in immediately available (same day) funds in such money.

 3.  Paying Agent and Registrar

     Initially,  The Bank of New  York  Trust  Company,  N.A.,  a United  States
banking association  ("Trustee"),  shall act as Paying Agent and Registrar.  The
Company may  appoint  and change any Paying  Agent,  Registrar  or  co-registrar
without notice. The Company or any of its domestically incorporated wholly owned
Subsidiaries may act as paying agent, Registrar or co-registrar.

 4.  Indenture

     The Company  issued the Securities  under an indenture  dated as of January
13, 1998,  between the Company and the  Trustee,  as  supplemented  by the sixth
supplemental  indenture  dated  as of  May  1,  2006  (the  "Sixth  Supplemental
Indenture,"  and,   collectively   with  the   aforementioned   indenture,   the
"Indenture"), among the Company, Pioneer Natural Resources USA, Inc., a Delaware
corporation  (the  "Guarantor"),  and the Trustee.  The terms of the  Securities
include  those stated in the  Indenture  and those made part of the Indenture by
reference to the Trust Indenture Act of 1939 (15 U.S.C. Sec. 77aaa-77bbbb) as in
effect on the date of the Indenture (the "Act").  Terms defined in the Indenture
and not defined herein have the meanings ascribed thereto in the Indenture.  The

                                       3






Securities are  subject to all  such  terms,  and  Holders  are  referred to the
Indenture and the Act for a statement of those terms.

     This  Security  is one of a duly  authorized  issue  of  general  unsecured
obligations of the Company all issued or to be issued under the Indenture.  Debt
Securities issued under the Indenture may be issued in one or more series, which
different  series  may be issued in various  aggregate  principal  amounts,  may
mature at  different  times,  may bear  interest at  different  rates,  may have
different  conversion  prices (if any),  may be subject to different  redemption
provisions,  may be subject to different  sinking,  purchase or analogous funds,
may be subject to  different  covenants,  Events of  Default  and  subordination
provisions  and may otherwise vary as the Indenture  provides.  This Security is
one of a series  designated as 6.875%  Senior Notes due 2018 (the  "Securities")
issued under the Indenture,  limited to $450,000,000 aggregate principal amount.
The Company may, without the consent of the Holders of the Notes,  increase such
aggregate  principal amount in the future,  on the same terms and conditions and
with the same CUSIP  numbers as the Notes.  The Company shall not issue any such
additional  Notes unless the  additional  Notes are fungible  with the Notes for
United  States  federal  income tax  purposes.  The  Indenture  imposes  certain
limitations (with significant  exceptions) on the ability of the Company and its
Subsidiaries  to  create  Liens on  assets  and  engage  in sale  and  leaseback
transactions.  This  Indenture  also imposes  limitations  on the ability of the
Company  to  consolidate,  merge or  transfer  all or  substantially  all of its
assets.

 5.  Obligation to Guarantee

     The Guarantor,  pursuant to the Sixth  Supplemental  Indenture,  has agreed
that,  if any of  certain  other  senior  notes  of the  Company  hereafter  are
guaranteed by the Guarantor then, it will at that time unconditionally guarantee
(a) the due and  punctual  payment of the  principal  of,  premium,  if any, and
interest on the  Securities,  whether at the maturity date, by  acceleration  or
otherwise,  and of interest on the overdue principal of and interest, if any, on
any premium and  interest of the  Securities  and all other  obligations  of the
Company to the Holders or the Trustee under the Indenture or the  Securities and
(b) in case of any extension of time of payment or renewal of any  Securities or
any of such other obligations,  that the same will be promptly paid in full when
due or  performed  in  accordance  with the terms of the  extension  or renewal,
whether at stated maturity, by acceleration or otherwise.

     The  obligations  of the Guarantor to the Holders and to the Trustee are as
expressly set forth in Section 3 of the Sixth Supplemental Indenture and in such
other  provisions  of the  Indenture as are  applicable  to the  Guarantor,  and
reference  is  hereby  made to such  Indenture  for the  precise  terms  of this
obligation  to  guarantee.  The terms of  Section  3 of the  Sixth  Supplemental
Indenture and such other  provisions  of the Indenture as are  applicable to the
Guarantor are incorporated herein by reference.

 6.  Optional Redemption

     The  Securities  will be  redeemable  at any  time,  at the  option  of the
Company,  in whole or from  time to time in part,  upon not less than 30 and not
more than 60 days'  notice as  provided in the  Indenture,  on any date prior to
their maturity (the "Redemption Date") at a price equal to 100% of the principal
amount thereof plus accrued and unpaid interest,  if any, to the Redemption Date

                                       4





(subject  to the  right of  Holders  of record on the  relevant  record  date to
receive  interest  due on an  interest  payment  date that is on or prior to the
Redemption Date) plus a Make-Whole  Premium,  if any,  calculated as provided in
Section 2 of the Sixth Supplemental  Indenture (the "Redemption  Price").  In no
event will a Redemption  Price ever be less than 100% of the principal amount of
the Securities plus accrued and unpaid interest, if any, to the Redemption Date.

 7.  Denominations; Transfer; Exchange

     The Securities are in registered form without coupons in  denominations  of
$1,000  and whole  multiples  of  $1,000.  A Holder  may  transfer  or  exchange
Securities  only in accordance  with the Indenture.  The Registrar may require a
Holder,  among other things,  to furnish  appropriate  endorsements  or transfer
documents  and to pay any taxes and fees  required  by law or  permitted  by the
Indenture.

 8.  Persons Deemed Owners

     The  registered  Holder of this  Security may be treated as the owner of it
for all purposes.

 9.  Unclaimed Money

     If money for the payment of principal or interest remains unclaimed for two
years,  the  Trustee or Paying  Agent shall pay the money back to the Company at
its request unless an abandoned  property law designates  another Person.  After
any such  payment,  Holders  entitled to the money must look only to the Company
and not to the Trustee for payment.

10.  Discharge and Defeasance

     Subject to certain  conditions,  the Company at any time may terminate some
or all its  obligations  under the  Securities  and the Indenture if the Company
deposits with the Trustee cash or U.S. Government Obligations for the payment of
principal and interest on the Securities to redemption or maturity,  as the case
may be.

11.  Amendment, Waiver

     Subject to certain exceptions set forth in the Indenture, (i) the Indenture
or the Securities  may be amended with the written  consent of the Holders of at
least a majority in principal amount  outstanding of the Securities and (ii) any
acceleration  of  principal  and  interest on the  Securities  resulting  from a
default or  noncompliance  with any  provision  may be waived  with the  written
consent of the  Holders of a majority in  principal  amount  outstanding  of the
Securities.  Subject  to  certain  exceptions  set  forth in  Article  IX of the
Indenture,  without the  consent of any Holder,  the Company and the Trustee may
amend  the  Indenture  or the  Securities  to  cure,  among  other  things,  any
ambiguity,  omission, defect or inconsistency,  or to evidence the succession of
another Person to the Company pursuant to Article X of the Indenture,  or to add
guarantees with respect to the Securities or to secure the Securities, or to add
additional covenants or surrender rights and powers conferred on the Company, or
to permit  the  qualification  of the  Indenture  under the Act,  or to make any
change that does not  adversely  affect the rights of any Holder,  or to provide
for the acceptance of a successor or separate Trustee.

                                       5






12.  Defaults and Remedies

     Under the Indenture,  Events of Default  include (i) default for 30 days in
payment of interest on the  Securities;  (ii) default in payment of principal or
premium on the Securities at maturity,  upon  acceleration  or otherwise;  (iii)
failure by the Company to comply with other  agreements  in the Indenture or the
Securities,  in certain  cases  subject to notice by Holders  and lapse of time;
(iv)  certain  accelerations  (including  failure to pay within any grace period
after final maturity) of other  Indebtedness of the Company or any Subsidiary of
the Company if the amount  accelerated  (or so unpaid)  exceeds  $20,000,000 and
continues  for 10 days after the  required  notice to the  Company;  (v) certain
events  of  bankruptcy  or  insolvency  with  respect  to the  Company  and  any
Significant  Subsidiary;  (vi)  certain  judgments or decrees for the payment of
money in excess of $20,000,000 and (vii) failure by the Guarantor to comply with
certain agreements in the Sixth Supplemental  Indenture.  If an Event of Default
occurs  and is  continuing,  the  Trustee  or the  Holders  of at  least  25% in
principal  amount of the Securities may declare all the Securities to be due and
payable  immediately.  Certain  events of bankruptcy or insolvency are Events of
Default  that will result in the  Securities  being due and payable  immediately
upon the occurrence of such Events of Default  without any action by the Trustee
or any Holders.

     Holders may not enforce the Indenture or the Securities  except as provided
in the  Indenture.  The  Trustee  may refuse to  enforce  the  Indenture  or the
Securities  unless it receives  reasonable  indemnity  or  security.  Subject to
certain limitations, Holders of a majority in principal amount of the Securities
may direct the Trustee in its  exercise  of any trust or power.  The Trustee may
withhold  from Holders  notice of any  continuing  Default  (except a Default in
payment of principal or interest) if it determines that withholding notice is in
the interest of the Holders.

13.  Trustee Dealings with the Company

     Subject to certain  limitations  imposed by the Act, the Trustee  under the
Indenture,  in its  individual  or any other  capacity,  may become the owner or
pledgee of Securities and may otherwise deal with and collect  obligations  owed
to it by the Company or its  Affiliates  and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

14.  No Recourse Against Others

     An incorporator and any past, present or future director, officer, employee
or  stockholder,  as such,  of the Company  shall not have any liability for any
obligations  of the Company  under the  Securities  or the  Indenture or for any
claim  based  on,  in  respect  of or by  reason  of such  obligations  or their
creation.  By  accepting a Security,  each Holder  waives and  releases all such
liability. The waiver and release are part of the consideration for the issue of
the Securities.

15.  Authentication

     This  Security  shall not be valid  until an  authorized  signatory  of the
Trustee  (or  an  authenticating   agent)  manually  signs  the  certificate  of
authentication on the other side of this Security.


                                       6





16.  Abbreviations

     Customary abbreviations may be used in the name of a Holder or an assignee,
such as TEN COM (=tenants in common),  TEN ENT (=tenants by the entireties),  JT
TEN (=joint tenants with rights of  survivorship  and not as tenants in common),
CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors Act).

17.  Governing Law

     THIS SECURITY  SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE  WITH, THE
LAWS OF THE STATE OF NEW YORK 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.

18.  CUSIP Numbers

     Pursuant  to a  recommendation  promulgated  by the  Committee  on  Uniform
Security  Identification  Procedures  the Company has caused CUSIP numbers to be
printed on the  Securities  and has directed the Trustee to use CUSIP numbers in
notices of redemption as a convenience to Holders.  No representation is made as
to the  accuracy  of such  numbers  either as  printed on the  Securities  or as
contained  in any notice of  redemption  and  reliance may be placed only on the
other identification numbers placed thereon.

     The Company  shall  furnish to any Holder upon written  request and without
charge  to the  Holder a copy of the  Indenture  that has in it the text of this
Security. Requests may be made to:

                               Corporate Secretary
                        Pioneer Natural Resources Company
                    5205 North O'Connor Boulevard, Suite 900
                                Irving, TX 75039


                                       7






                                 ASSIGNMENT FORM



To assign this Security, fill in the form below:



I or we assign and transfer this Security to



- -------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)



- -------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably  appoint  __________________  agent to transfer this Security on
the books of the Company. The agent may substitute another to act for him.





Date:                         Your Signature:
     --------------------                     ---------------------------------



Sign exactly as your name appears on the other side of this Security.



Date:                         Your Signature:
     --------------------                     ---------------------------------

                                           (Sign exactly as your name appears on
                                           the other side of the Security)



Signature Guarantee:
                      ---------------------------------------------------------

                      (Signature must be guaranteed by a  member firm of the New
                      York Stock Exchange or a commercial bank or trust company)


                                       8