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                                                                    EXHIBIT 99.1

CERTIFICATION PURSUANT TO RULE 13a-14 OR 15d-14 OF THE SECURITIES EXCHANGE ACT
OF 1934, AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Phillip E. Casey, certify that:

1.    I have reviewed this annual report on Form 40-F of Gerdau Ameristeel
      Corporation;

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 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;

      (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

      (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

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 function):

      (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.

Dated: March 29, 2005

                                           /s/ Phillip E. Casey
                                           ---------------------
                                           Phillip E. Casey
                                           Chief Executive Officer (Principal
                                           Executive Officer)