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                                                                    EXHIBIT 12.1

                                 CERTIFICATIONS

         I, Svein Rennemo, certify that:

                  1.    I have reviewed this annual report on Form 20-F of
Petroleum Geo-Services ASA;

                  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;

                  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 company as of, and for, the periods presented in this report;

                  4.    The company's other certifying officer(s) 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)) for the company and
have:

                  (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
         company, 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;

                  (b)   Evaluated the effectiveness of the company'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

                  (c)   Disclosed in this report any change in the company'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 company's internal control
         over financial reporting; and

                  5.    The company's other certifying officer(s) and I have
disclosed, based on our most recent evaluation of internal control over
financial reporting, to the company's auditors and the audit committee of the
company's board of directors (or persons performing the equivalent functions):

                  (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 company's ability
         to record, process, summarize and report financial information; and

                  (b)   Any fraud, whether or not material, that involves
         management or other employees who have a significant role in the
         company's internal control over financial reporting.

Date:  November 16, 2004


By:      /s/ Svein Rennemo
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      Svein Rennemo
      President and Chief Executive Officer