<PAGE>
                                                                    EXHIBIT 4.11

            AMENDMENT NO. 9 TO AMENDED AND RESTATED CREDIT AGREEMENT

         THIS AMENDMENT dated as of March 31, 2005, and effective as of March
31, 2005 by and among the financial institutions whose signatures appear below
(individually a "Bank," collectively the "Banks"), Comerica Bank, as
Administrative Agent for the Banks (in such capacity, "Agent"), and Olympic
Steel, Inc., an Ohio corporation (the "Company").

         RECITALS:

         A. Company, Agent and Comerica Bank, Fifth Third Bank, Standard Federal
Bank N.A., Fleet Capital Corporation and KeyBank National Association are
parties to that certain Amended and Restated Credit Agreement dated as of
December 30, 2002, as previously amended ("Credit Agreement").

         B. Company, the Banks and Agent desire to amend the Credit Agreement as
set forth below.

         NOW THEREFORE, the parties agree as follows:

         1. The definition of "Revolving Credit Aggregate Commitment" set forth
in Section 1.1 of the Credit Agreement are amended to read as follows:

              `Revolving Credit Aggregate Commitment' shall mean (i) from March
         31, 2005 through June 30, 2005, One Hundred Thirty Million Dollars
         ($130,000,000) and (ii) commencing July 1, 2005 and thereafter, One
         Hundred Ten Million Dollars ($110,000,000), in either case, subject to
         reduction or termination under Section 2.13, 2.14 or 9.2 hereof."

         2. Schedule 1.2 of the Agreement is amended to read in the form annexed
hereto.

         3. On July 1, 2005, Company shall repay the indebtedness outstanding
under the Revolving Credit Notes to the extent such indebtedness exceeds One
Hundred Ten Million Dollars ($110,000,000).

         4. The Obligations, as increased by this Amendment, continue to be
secured by the liens on and security interest in the Collateral under terms of
the Collateral Documents.

         5. Upon execution of this Amendment, Company agrees to pay to the Agent
a $5,000 non-refundable fee for each of the Banks executing this Amendment (an
aggregate payment of Twenty Five Thousand Dollars ($25,000)).

         6. Except as expressly modified hereby, all the terms and conditions of
the Credit Agreement shall remain in full force and effect.

         7. Company hereby represents and warrants that, after giving effect to
the amendments contained herein, (a) execution, delivery and performance of this
Amendment and any other documents and instruments required under this Amendment
or


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the Credit Agreement are within its corporate powers, have been duly authorized,
are not in contravention of law or the terms of its Articles of Incorporation or
Bylaws, and do not require the consent or approval of any governmental body,
agency, or authority; and this Amendment and any other documents and instruments
required under this Amendment or the Credit Agreement, will be valid and binding
in accordance with their terms; (b) the continuing representations and
warranties made by Company set forth in Sections 6.1 through 6.19 and 6.21
through 6.24 of the Credit Agreement are true and correct on and as of the date
hereof with the same force and effect as if made on and as of the date hereof;
(c) the continuing representations and warranties of Company set forth in
Section 6.20 of the Credit Agreement are true and correct as of the date hereof
with respect to the most recent financial statements furnished to the Bank by
Company in accordance with Section 7.1 of the Credit Agreement; and (d) no
Default or Event of Default has occurred and is continuing as of the date
hereof.

         8. Capitalized terms used but not defined herein shall have the meaning
set forth in the Credit Agreement.

         9. This Amendment may be signed in counterparts.

         10. This Amendment shall become effective (according to the terms and
as of the date hereof) upon satisfaction by Company of the following conditions:

                  (a) Agent shall have received counterpart originals of this
         Amendment, in each case duly executed and delivered by Company, the
         Agent, the Banks, and the Guarantors and originals of the Loan
         Documents identified on the Closing Agenda annexed hereto duly executed
         by the parties thereto and, where applicable, in recordable form; and

                  (b)      Company shall have paid to the Agent for the benefit
         of the Banks the fee required in paragraph 5, above.


                     [REMAINDER OF PAGE INTENTIONALLY BLANK]


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<PAGE>


         WITNESS the due execution hereof as of the day and year first above
written.


COMERICA BANK,                         OLYMPIC STEEL, INC.
as Agent


By:                                    By:
   ---------------------------            --------------------------------------

Its:                                   Its:
    --------------------------             -------------------------------------



SWING LINE BANK:                       COMERICA BANK



                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------



ISSUING BANK:                          COMERICA BANK

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


BANKS:                                 COMERICA BANK


                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


                                       STANDARD FEDERAL BANK N.A.

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------



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<PAGE>


                                       FIFTH THIRD BANK

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


                                       FLEET CAPITAL CORPORATION

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


                                       KEYBANK NATIONAL ASSOCIATION

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


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<PAGE>


Acknowledged by the undersigned Guarantor as of March 31, 2005.


                                       GUARANTORS:

                                       OLYMPIC STEEL LAFAYETTE, INC.

                                       By:
                                          --------------------------------------

                                       Its:
                                           -------------------------------------


                                       OLYMPIC STEEL MINNEAPOLIS,
                                          INC.

                                       By:
                                          --------------------------------------


                                       Its:
                                           -------------------------------------



                                       OLYMPIC STEEL IOWA, INC.

                                       By:
                                          --------------------------------------


                                       Its:
                                           -------------------------------------



                                       OLY STEEL WELDING, INC.

                                       By:
                                          --------------------------------------


                                       Its:
                                           -------------------------------------



                                       OLYMPIC STEEL RECEIVABLES,
                                          L.L.C.

                                       By:
                                          --------------------------------------


                                       Its:
                                           -------------------------------------


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