I. Purpose


The Board of Directors (the "Board") of Pioneer Natural Resources Company (the "Company") has established the Audit Committee (the "Committee") of the Board. The purposes of the Committee are to assist the Board in fulfilling its oversight responsibilities by:

A.                 overseeing the reliability and integrity of the Company's financial statements, accounting policies, and financial reporting and disclosure practices,

B.                  overseeing the Company's compliance with legal and regulatory requirements,

C.                 overseeing the independent auditor's qualifications and independence

D.                 overseeing the performance of the Company's internal audit function and any independent internal auditors,

E.                  overseeing the Company's systems of internal controls regarding finance, accounting, legal compliance and ethics that management and the Board have established,

F.                  reviewing and appraising the audit efforts of the Company's independent auditors and internal auditing department (reference to internal auditors or the internal audit department in this Charter shall include both internal audit activities and functions conducted by employees of the Company or by outside auditors engaged for such purposes) and, where appropriate, replacing the independent auditors or internal audit department,

G.                 providing an open avenue of communication among the independent auditors, financial and senior management, the internal auditors or department, and the Board, always emphasizing that the independent auditors are ultimately accountable to the Committee and the Board, and

H.                 preparing annually the report the SEC rules require be included in the proxy statement relating to the Company's annual meeting of stockholders, and

I.                   performing such other duties as are directed by the Board.

Consistent with this Purpose, the Committee should encourage continuous improvement of, and should foster adherence to, the Company's policies, procedures and practices at all levels. The Committee will primarily fulfill these responsibilities by carrying out the activities enumerated in Section V of this Charter.


II. Composition


The Committee shall be comprised of three or more Directors, as determined by the Board or a nominating committee of the Board, none of whom shall be an affiliate of the Company or an employee or a person who receives any compensation from the Company other than fees paid for service as a Director. The members of the Committee shall be elected by the Board or a nominating committee of the Board annually and shall serve until their successors shall be duly elected and qualified. Each member shall be "independent" as defined from time to time by the listing standards of the New York Stock Exchange (the "NYSE") and by applicable regulations of the Securities and Exchange Commission (the "SEC") and shall meet any other applicable independence requirements of the NYSE and SEC. Accordingly, the Board shall determine annually whether each member is free from any relationship that may interfere with his or her independence from management and the Company. No member shall serve on an audit committee of more than two other public companies unless the Board determines that such simultaneous service would not impair the ability of such director to effectively serve on the Committee.

Each member shall be (or shall become within a reasonable time after appointment) financially literate, and at least one member shall be a "financial expert" as defined from time to time by applicable regulations of the SEC. Members of the Committee may enhance their familiarity with finance and accounting principles by participating in educational programs that the Company or an outside consultant conducts.

Notwithstanding the foregoing membership requirements, no action of the Committee shall be invalid by reason of any such requirement not being met at the time such action is taken.


III. Meetings and Structure


The Committee shall meet at least four times per year to review the financial information of the Company, consistent with its duties and responsibilities, and as many additional times as the members deem necessary. As a part of its effort to foster open communications, the Committee should meet at least annually with management, the director of the internal auditing department, and the independent auditors in separate executive sessions to discuss any matters that the Committee or each of these groups believe should be discussed privately.

Unless the Board designates a Chair of the Committee, the members of the Committee shall, by majority vote of the full Committee membership, appoint one member of the Committee as chairperson. He or she shall be responsible for leadership of the Audit Committee, including preparing the agenda, presiding over the meetings, making committee assignments and reporting to the Board. The chairperson will also maintain regular liaison with the Chief Executive Officer, the Chief Financial Officer, the lead audit partner of the Company's independent auditors and the Company's internal auditor.


IV. Accountability of the Independent Auditors


The independent auditors are accountable to the Committee. The Committee shall have the sole authority and responsibility with respect to the selection, engagement, compensation, oversight, evaluation and, where appropriate, dismissal of the Company's independent auditors. The Committee, or a member thereof, must pre-approve any non-audit service provided to the Company by the Company's independent auditors.


V. Authority and Responsibilities


The Committee shall have the authority to take all actions it deems advisable to fulfill its responsibilities and duties. The Committee shall have the authority to retain professional advisors including, without limitation, special legal counsel, accounting experts, or other consultants to advise the Committee, which may be the same as or different from the Company's primary legal counsel, accounting experts and other consultants as the Committee deems necessary or advisable in connection with the exercise of its powers and responsibilities as set forth in this Audit Committee Charter, all on such terms as the Committee deems necessary and advisable. The Committee may require any officer or employee of the Company or any of its subsidiaries, the Company's outside legal counsel, and the Company's external auditors to attend a meeting of the Committee or to meet with any member of, or consultant to, the Committee. The Committee chairperson, or other designee of the Committee, may also meet with the Company's investment bankers or financial analysts who follow the Company.

The Committee shall be responsible for the resolution of any disagreements between the independent auditors and management regarding the Company's financial reporting.

The Company shall provide for appropriate funding, as determined by the Committee, for payment of compensation to the independent auditors employed by the Company for the purpose of rendering or issuing an audit report and to any special legal counsel, accounting experts or other consultants employed by the Committee.

To further fulfill the purpose, powers and responsibilities set forth above, the Committee shall also:

A.                 Independent Auditors

Annually select and engage the Company's independent auditors retained to audit the financial statements of the Company with such selection to be submitted to the stockholders for ratification, if the Board of Directors so chooses.

Review the performance of the independent auditors and approve any proposed discharge of the independent auditors when circumstances warrant.

Review and pre-approve the plan and scope of the independent auditors' auditing services (including comfort letters), non-audit services and related fees. The Company shall disclose any non-audit services approved by the Audit Committee in the Company's periodic reports filed with the SEC.

Ensure that the lead audit partner and reviewing audit partner of the Company's independent auditors are rotated at least every five years.

Set clear hiring policies for employees or former employees of the Company's independent auditors.

Periodically obtain and review a report from the independent auditors regarding all relationships between the independent auditors and the Company that may affect the independent auditors' objectivity and independence, and discuss the report with the independent auditors. The Committee shall also recommend any appropriate action to the Board in response to the written report necessary to satisfy itself of the independence and objectivity of the independent auditors.

Periodically obtain and review reports from the independent auditors that include (i) all alternative treatments of financial information within generally accepted accounting principles ("GAAP") that have been discussed with management, their ramifications and the preferences of the independent auditors, and (ii) other material written communications between the independent auditors and management.

Review and approve the appointment, termination or replacement by management of a Director of Internal Auditing or, at the discretion of the Board, select and contract with outside auditors to perform the function of an internal audit department.

Direct the scope of the duties and activities of the Director of Internal Auditing or any outside auditors serving as internal auditors, who shall report directly to the Audit Committee.

B.                  Review

Periodically obtain and review reports from the independent auditors that include all critical accounting policies and practices used.

Review with management and the independent auditors the Company's quarterly or annual financial information including matters required to be reviewed under applicable legal, regulatory or NYSE requirements prior to the filing of the Company's Quarterly Report on Form 10-Q or Annual Report on Form 10-K, as the case may be, or prior to the release of earnings.

Discuss with financial management the Company's earnings releases, including the use of "pro forma", "adjusted" or other non-GAAP measures, as well as financial information and earnings guidance, if any, provided to the public, analysts or rating agencies.

Review and discuss with management and the independent auditors the disclosures made in management's discussion and analysis of financial condition and results of operations in any of the Company's reports on Form 10-Q or Form 10-K.

Upon completion of any annual audit, meet separately with the independent auditors and management and review the Company's financial statements and related notes, the results of their audit, any report or opinion rendered in connection therewith, any significant difficulties encountered during the course of the audit, including any restrictions on the scope of work or access to required information, any significant disagreements with management concerning accounting or disclosure matters and any significant adjustment proposed by the independent auditors.

Regularly review with the Company's independent auditors any audit problems or difficulties and management's response.

Review and consider with the independent auditors and management the matters required to be discussed by Statement of Auditing Standards No. 61. These discussions shall include consideration of the quality of the Company's accounting principles as applied in its financial reporting, including review of estimates, reserves and accruals, review of judgmental areas, review of audit adjustments whether or not recorded and such other inquiries as may be appropriate.

Based on the foregoing review, make recommendation to the Board as to the inclusion of the Company's audited financial statements in the Company's annual report on Form 10-K.

Review any disclosures provided by the Chief Executive Officer or the Chief Financial Officer to the Committee regarding significant deficiencies in the design or operation of internal controls which could adversely affect the Company's ability to record, process, summarize, and report financial data.

Review with management and the independent auditors any significant transactions that are not a normal part of the Company's operations and changes, if any, in the Company's accounting principles or their application.

At least annually, obtain and review a report by the independent auditors describing the firm's internal quality-control procedures; any material issues raised by the most recent internal quality-control review, or peer review, of the firm, or by any inquiry or investigation by governmental or professional authorities, within the preceding five years, respecting one or more independent audits carried out by the firm, and any steps taken to deal with any such issues.

Periodically meet and review with the Director of Internal Auditing the regular internal reports to management prepared by the internal auditing department and the progress of activities and any findings of major significance stemming from internal audits.

C.                 Financial Reporting Processes

Periodically discuss separately with management, the independent auditors and the internal auditors the adequacy and integrity of the Company's accounting policies and procedures and internal accounting controls, the completeness and accuracy of the Company's financial disclosure and the extent to which major recommendations made by the independent auditors or the internal auditors have been implemented or resolved.

Consider and approve, if appropriate, major changes to the Company's auditing and accounting principles and practices as suggested by the independent auditors, management, or the internal auditing department.

Review with the independent auditors, the internal auditing department and management the extent to which such changes have been implemented. This review should be conducted at an appropriate time subsequent to implementation of changes, as the Committee determines.

D.                 Process Improvement

Establish regular and separate systems of reporting to the Audit Committee by each of management, the independent auditors and the Director of Internal Auditing regarding any significant judgments made in management's preparation of the financial statements and the view of each as to appropriateness of such judgments.

Conduct annual evaluation with the Board regarding the performance of the Audit Committee.

Discuss with management and the Director of Internal Accounting policies with respect to risk assessment and risk management.

Regularly apprise the Board, through minutes and special presentations as necessary, of significant developments in the course of performing these duties.

E.                  Ethical and Legal Compliance

Establish procedures for the receipt, retention and treatment of complaints received regarding accounting, internal accounting controls, auditing matters and the confidential, anonymous submissions by employees of concerns regarding questionable accounting or auditing matters.

Review any disclosures provided by the Chief Executive Officer or the Chief Financial Officer to the Committee regarding (i) significant deficiencies in the design or operation of internal controls which could adversely affect the Company's ability to record, process, summarize and report financial data; and (ii) any fraud, including that which involves management or other employees who have a significant role in the Company's internal controls.

Investigate at its discretion any matter brought to its attention by, without limitation, reviewing the books, records and facilities of the Company and interviewing Company officers or employees.

Review management's monitoring of the Company's compliance programs and evaluate whether management has review systems in place designed to ensure that the Company's financial statements, reports and other financial information disseminated to governmental organizations and the public satisfy applicable legal, regulatory or NYSE requirements.

Review with the Company's in-house or outside legal counsel any legal matter that could have a significant effect on the Company's financial statements, including the status of pending litigation, taxation matters and other areas of oversight to the legal and compliance area as may be appropriate.

Review with management and the independent auditors the Company's policies and procedures regarding compliance with its internal policies as well as applicable laws and regulations, including without limitation with respect to maintaining books, records and accounts and a system of internal accounting controls in accordance with Section 13(b)(2) of the Securities Exchange Act of 1934.

F.                  General

Perform any other activities consistent with this Charter, the Company's Certificate of Incorporation and Bylaws, the rules of the NYSE applicable to its listed companies, and governing law as the Audit Committee or the Board deems necessary or appropriate.


VI. Review of Committee Charter


At least annually, the Committee shall review and reassess the adequacy of this Charter. The Committee shall report the results of the review to the Board and, if necessary, make recommendations to the Board to amend this Charter.


VII. Limitations


While the Committee has the responsibilities and powers set forth in this Charter and management and the independent auditors for the Company are accountable to the Committee, it is not the duty of the Committee to plan or conduct audits or to determine that the Company's financial statements are complete and accurate and are in accordance with GAAP. This is the responsibility of management.