# Exhibit 99.1

CERTIFICATION

I, Serge Godin, certify
that:

1.    
          I have reviewed this annual report on Form 40-F of CGI Group, Inc.;

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

4.    
          The issuer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 issuer 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 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) 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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| | (c) 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(s) 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):

| | (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 internal control over financial
                    reporting.
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Date: February 7, 2005

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| | /s/ Serge Godin              Serge Godin
Chairman of the Board and
  Chief Executive Officer