**CERTIFICATION        PURSUANT TO SECTION 302 OF SARBANES-OXLEY ACT**

| 1. | I                  have reviewed this annual report on Form 40-F of Petro-Canada; |
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| 2. | Based                  on my knowledge, this report does not contain any untrue statement                  of a                  material fact or omit to state a material fact necessary to make                  the                  statements made, in light of the circumstances under which such                  statements                  were made, not misleading with respect to the period covered by                  this                  report; |
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| 3. | Based                  on my knowledge, the financial statements, and other financial                  information                  included in this report, fairly present in all material respects                  the                  financial condition, results of operations and cash flows of the                  issuer as                  of, and for, the periods presented in this report; |
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| 4. | The                  issuer's other certifying officer and I are responsible for establishing                  and maintaining disclosure controls and procedures (as defined                  in Exchange                  Act Rules 13a-15(e) and 15d-15(e)) and                  internal control over financial reporting (as defined in Exchange                  Act                  Rules 13a-15(f) and 15d-15(f)) for                  the issuer and have: |
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|   | a) | designed                  such disclosure controls and procedures, or caused such disclosure                  controls and procedures to be designed under our supervision, to                  ensure                  that material information relating to the issuer, including its                  consolidated subsidiaries, is made known to us by others within                  those                  entities, particularly during the period in which this report is                  being                  prepared; |
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|   | b) | designed                  such internal control over financial reporting, or caused such                  internal                  control over financial reporting to be designed under our supervision,                  to                  provide reasonable assurance regarding the reliability of financial                  reporting and the preparation of financial statements for external                  purposes in accordance with generally accepted accounting                  principles;  |
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|   | c) | evaluated                  the effectiveness of the issuer's disclosure controls and procedures                  and                  presented in this report our conclusions about the effectiveness                  of the                  disclosure controls and procedures, as of the end of the period                  covered by                  this report based on such evaluation;                  and |
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|   | d) | disclosed                  in this report any change in the issuer's internal control over                  financial                  reporting that occurred during the period covered by the annual                  report                  that has materially affected, or is reasonably likely to materially                  affect, the issuer's internal control over financial reporting;                  and |
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| 5. | The                  issuer's other certifying officer and I have disclosed, based on                  our most                  recent evaluation of internal control over financial reporting,                  to the                  issuer's auditors and the audit committee of the issuer's board                  of                  directors (or persons performing the equivalent functions): |
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|   | a) | all                  significant deficiencies and material weaknesses in the design                  or                  operation of internal control over financial reporting which are                  reasonably likely to adversely affect the issuer's ability to record,                  process, summarize and report financial information;                  and |
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|   | b) | any                  fraud, whether or not material, that involves management or other                  employees who have a significant role in the issuer's control over                  financial reporting. |
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|  Date:                  March 29, 2007 |  /s/                  E. F. H. RobertsE.                  F. H. RobertsExecutive                  Vice-President and |
|                                        | Chief                  Financial Officer                                                                                  |