UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON DC 20549

                                    FORM 10-Q/A

/X/      QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

For the quarterly period ended        March 31, 2003
                               -------------------------------------------------

                                       OR

/ /      TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

For the transition period from                       to
                               ---------------------    ------------------------

Commission File Number       1-9887
                       --------------------

                            OREGON STEEL MILLS, INC.
             (Exact name of registrant as specified in its charter)

                   Delaware                                  94-0506370
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         (State or other jurisdiction of                   (IRS Employer
          incorporation or organization)                    Identification No.)

 1000 S.W. Broadway, Suite 2200, Portland, Oregon                       97205
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(Address of principal executive offices)                              (Zip Code)

                                 (503)223-9228
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              (Registrant's telephone number, including area code)

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   (Former name, former address and former fiscal year, if changed since
    last report)

         Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Sections 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                                    Yes X    No
                                       ---     ---

Indicate by check mark whether the registrant is an accelerated filer
(as defined in Rule 12b-2 of the Exchange Act).
                                    Yes X    No
                                       ---     ---

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of the latest practical date:

         Common Stock, $.01 Par Value                  26,388,254
         ----------------------------        -----------------------------------
                    Class                      Number of Shares Outstanding
                                                  (as of May 1, 2003)