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EXHIBIT 12.1

CERTIFICATION PURSUANT TO SECTION 302 OF SARBANES-OXLEY ACT

I, André Tremblay, certify that:



| | 1. |  | I have reviewed this annual report on Form 20-F of Microcell
Telecommunications Inc.;                                                                                                                                                                                                                     
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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 company as of, and for, the periods presented in this report;                      
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| | 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:                                                                                



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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
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;
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| | (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                                                                                           
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| | (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):
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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 company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 companys internal
control over financial reporting.

Date: March 3, 2004



| | /s/ André Tremblay
André Tremblay
President and Chief Executive Officer
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