8-K

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON DC 20549

                                    FORM 8-K
                                 CURRENT REPORT
                       PURSUANT TO SECTION 13 OR 15(D) OF
                       THE SECURITIES EXCHANGE ACT OF 1934
       DATE OF REPORT (DATE OF EARLIEST EVENT REPORTED): JANUARY 31, 2005

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

    DELAWARE                             1-9887               94-0506370
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(State or other jurisdiction         (Commission            (IRS Employer
 of incorporation)                    File Number)           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)


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

[ ]  Written communications pursuant to Rule 425 under the Securities Act
     (17 CFR 230.425)

[ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
     (17 CFR 240.14a-12)

[ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
     Exchange Act (17 CFR 240.14d-2(b))

[ ]  Pre-commencement communications pursuant to Rule 13e-4 (c) under the
     Exchange Act (17 CFR 240.13e-4 (c))





ITEM 8.01  OTHER EVENTS

On January 31, 2005, Oregon Steel Mills, Inc. issued a press release, announcing
that the Company is increasing its fourth quarter 2004 earnings estimate.

The Company provides in the press release an estimate of net income exclusive of
labor dispute settlement adjustments, a non-GAAP financial measure. The Company
believes the non-GAAP measure is useful to investors when comparing to prior
periods because it believes the excluded items are non-recurring. The Company's
management uses this non-GAAP financial measure along with the most directly
comparable GAAP financial measure in evaluating the Company's operating
performance.

The Company's press release is attached as exhibit 99.1.

ITEM 9.01  FINANCIAL STATEMENTS AND EXHIBITS


(c)  Exhibits

EXHIBIT
NUMBER            DESCRIPTION

99.1     Oregon Steel Mills, Inc. Company Press Release dated January 31, 2005,
         announcing that the Company is increasing its fourth quarter 2004
         earnings estimate.



                                   SIGNATURES

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

                            OREGON STEEL MILLS, INC.
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                                  (Registrant)



Date:  January 31, 2005                    By:    /s/ Jeff S. Stewart
       -----------------------------          ----------------------------------
                                                  Jeff S. Stewart
                                                  Corporate Controller
                                                  (Principal Accounting Officer)

EX-99

EXHIBIT 99.1

                            OREGON STEEL MILLS, INC.
                                Portland, Oregon

FOR IMMEDIATE RELEASE                                         January 31, 2005
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Contact:     Ray Adams
             Chief Financial Officer
             (503) 240-5223


                    OREGON STEEL MILLS INCREASES 2004 FOURTH
                            QUARTER EARNINGS ESTIMATE


Portland, Oregon, January 31, 2005/Business Wire/--Oregon Steel Mills, Inc.
(NYSE: OS) announced today it is increasing its fourth quarter 2004 earnings
estimate. In early November, Oregon Steel forecasted fourth quarter net income
from continuing operations within a range of $1.05 to $1.15 per diluted share,
exclusive of any further labor dispute settlement adjustments. The Company now
estimates fourth quarter net income from continuing operations of $1.25 to $1.35
per diluted share based on approximately 35.1 million diluted weighted average
shares outstanding during the fourth quarter of 2004. These amounts exclude the
estimated $4.5 million charge (approximately $.13 per diluted share) in the
fourth quarter of 2004 related to the previously disclosed early retirement
option offered to certain union employees of the Company. The Company expects to
have an effective income tax rate of approximately three percent in the fourth
quarter of 2004. The Company notes that the expected improved results will be
due, in part, to higher than anticipated plate demand and plate pricing and
lower than forecasted scrap prices.

The Company will announce its final 2004 annual and fourth quarter financial
results and provide its outlook for 2005 during the first week of March 2005.

FORWARD-LOOKING STATEMENTS

Forward-looking statements in this release are made pursuant to the safe harbor
provisions of the Private Securities Litigation Reform Act of 1995. Such
forward-looking statements are subject to risks and uncertainties and actual
results could differ materially from those projected. Such risks and
uncertainties include, but are not limited to, general business and economic
conditions; competitive products and pricing, as well as fluctuations in demand;
cost and availability of raw materials; potential equipment malfunction; and
plant construction and repair delays. For more detailed information, please
review the discussion of risks, which may cause results to differ materially, in
the Company's most recently filed Form 10-K, Form 10-Q and other SEC reports.


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These forward-looking statements should not be relied upon as representing the
Company's views as of any subsequent date and the Company undertakes no
obligation to update or revise the forward-looking statements, whether as a
result of new information, future events or otherwise, after the date they are
made.

Oregon Steel Mills, Inc. is organized into two divisions. The Oregon Steel
Division produces steel plate, coil, welded pipe and structural tubing from
plants located in Portland and Camrose, Alberta, Canada. The Rocky Mountain
Steel Mills Division, located in Pueblo, Colorado, produces steel rail, rod,
bar, and tubular products.

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