EXHIBIT 5.1          OPINION OF SCHWABE, WILLIAMSON & WYATT, P.C.



                                                April 25, 2002
                                               ----------
Oregon Steel Mills, Inc.
1000 SW Broadway, Suite 2200
Portland, Oregon  97205

Ladies and Gentlemen:

         We are acting as counsel to Oregon Steel Mills, Inc., a Delaware
Corporation (the "COMPANY"), in connection with the Registration Statement on
Form S-8 (the "REGISTRATION STATEMENT"), filed by the Company under the
Securities Act of 1933, relating to the registration of up to 150,000 shares
("SHARES") of the common stock, $.01 par value (the "COMMON STOCK"), of the
Company issuable under the Company's 2002 Non-Employee Director Stock Option
Plan (the "PLAN").

         We have examined and relied upon originals or copies, certified or
otherwise identified to our satisfaction, of the Company's Restated Certificate
of Incorporation, as amended, the Company's By-laws as currently in effect, the
Registration Statement, the Plan, and such other corporate documents and records
and other certificates, and we have made such investigations of law, as we have
deemed necessary to render this opinion.

         Based upon and subject to the foregoing, we are of the opinion that the
Shares, when issued in accordance with the Plan and the respective stock option
agreements issued thereunder (including payment of the option exercise price
provided for therein), will be legally issued, fully paid and nonassessable
under the Delaware General Corporation Law, the Delaware Constitution, and
reported judicial decisions thereunder.

         We consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement. In giving our consent we do not admit that we are within
the category of persons whose consent is required under Section 7 of the
Securities Act or the rules and regulations of the Securities and Exchange
Commission.

                                         Very truly yours,

                                         /s/ Schwabe, Williamson & Wyatt, P.C.

                                         SCHWABE, WILLIAMSON & WYATT, P.C.