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                                    FORM 6-K
                     U.S. SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                        REPORT OF FOREIGN PRIVATE ISSUER
                   PURSUANT TO RULE 13A-16 OR 15D-16 UNDER THE
                         SECURITIES EXCHANGE ACT OF 1934

                             dated September 1, 2005


                         Commission File Number 1-14878


                                   GERDAU S.A.
                    (Exact Name as Specified in its Charter)

                                       N/A
                                   ----------
                       (Translation of Registrant's Name)

                                Av. Farrapos 1811
             Porto Alegre, Rio Grande do Sul - Brazil CEP 90220-005
                    (Address of principal executive offices)


         Indicate by check mark whether the registrant files or will file annual
reports under cover Form 20-F or Form 40-F.

         Form 20-F    X    Form 40-F      
                    -----            -----

         Indicate by check mark if the registrant is submitting the Form 6-K in
paper as permitted by Regulation S-T Rule 101(b)(1):
                                                     ----

         Indicate by check mark if the registrant is submitting the Form 6-K in
paper as permitted by Regulation S-T Rule 101(b)(7):
                                                     ----

         Indicate by check mark whether by furnishing the information contained
in this Form, the registrant is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

         Yes                        No    X  
             ----                      ------

         If "Yes" is marked, indicate below the file number assigned to the
registrant in connection with Rule 12g3-2(b): Not applicable.


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                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of
1934, the registrant has duly caused the Report to be signed on its behalf by
the undersigned, thereunto duly authorized.


Date:  September 1, 2005

                                    GERDAU S.A.




                                    By:  /s/ Osvaldo Burgos Schirmer
                                         ---------------------------------------
                                          Name:  Osvaldo Burgos Schirmer
                                          Title: Chief Financial Officer




                                  EXHIBIT INDEX




Exhibit               Description of Exhibit
-------               ----------------------

99.1                  Release, August 31, 2005