Exhibit 5


                         [Letterhead of Arnold & Porter]



                                February 3, 1999



Armco Inc.
One Oxford Centre
301 Grant Street
Pittsburgh, Pennsylvania  15219


Ladies and Gentlemen:

        We refer to the registration statement on Form S-4, Registration No. 
333-71203 (the "Registration Statement"), filed by Armco Inc., an Ohio 
corporation (the "Company"), with the Securities and Exchange Commission 
under the Securities Act of 1933, as amended (the "Act"), pursuant to which 
the Company is registering $75,000,000 aggregate principal amount of 8 7/8% 
Senior Notes due 2008 (the "Exchange Notes"), under an Indenture dated as of 
November 1, 1993 between the Company and Star Bank, N.A., as trustee (the 
"Trustee"), as supplemented by Supplemental Indenture No. 1, dated as of 
November 1, 1993, and Supplemental Indenture No. 2, dated as of December 15, 
1998 (the "Indenture"), to be issued in exchange for $75,000,000 aggregate 
principal amount of the Company's outstanding 8 7/8% Senior Notes due 2008 
(the "Exchange Offer").  The terms and conditions of the Exchange Notes and 
the Exchange Offer are as set forth in the Registration Statement and the 
prospectus (the "Prospectus") contained therein.

        We have examined originals or copies, certified or otherwise 
identified to our satisfaction, of the Registration Statement, the Indenture, 
the form of Exchange Notes set forth in the Indenture, and such corporate 
records, agreements, documents and other instruments, and such certificates 
or comparable documents of public officials and of officers and 
representatives of the Company, and have made such inquiries of such officers 
and representatives as we have deemed relevant and necessary as a basis for 
the opinions hereinafter set forth.

        Based upon and subject to the foregoing, we are of the opinion that 
the Exchange Notes have been duly authorized by the Company and when the 
Exchange Notes have been duly executed by the Company and authenticated by 
the Trustee in accordance with 



the terms of the Indenture and issued in exchange for the Old Notes in 
accordance with the terms of the Exchange Offer, the Exchange Notes will 
constitute valid and binding obligations of the Company under the laws of the 
State of New York, subject to bankruptcy, insolvency, reorganization, 
fraudulent conveyance, moratorium, receivership and similar laws relating to 
or affecting creditors' rights generally and to equitable principles 
(regardless of whether enforcement is sought in a proceeding in equity or at 
law).

        The foregoing opinion is limited to the laws of the State of New York 
and, in reliance upon the opinion of Gary R. Hildreth, General Counsel of the 
Company, an executed copy of which is attached hereto (the "Hildreth 
Opinion"), the laws of the State of Ohio, and we do not express any opinion 
herein concerning the laws of any other jurisdiction.  To the extent the 
foregoing opinion relates to matters governed by the laws of the State of 
Ohio, such opinion is subject to the qualifications and limitations expressed 
in the Hildreth Opinion.

        We hereby consent to the filing of this opinion as an exhibit to the 
Registration Statement and to the reference to this firm under the heading 
"Legal Matters" in the Registration Statement.  In giving the foregoing 
consent, we do not thereby admit that we are in the category of persons whose 
consent is required under Section 7 of the Act or the rules and regulations 
of the Securities and Exchange Commission thereunder. 

        This opinion is solely for your information and is not to be quoted 
in whole or in part, summarized or otherwise referred to without our written 
consent, except as provided in the preceeding paragraph.  This opinion is as 
of the date hereof.  We disclaim any responsibility to update or supplement 
this opinion to reflect any events or state of facts which may hereafter come 
to our attention or any changes in statutes or regulations or any court 
decisions which may hereafter occur.

                                                Very truly yours,

                                                /s/ ARNOLD & PORTER








                                                       Attachment to Exhibit 5




                          [Letterhead of Armco]



                            February 3, 1999



Arnold & Porter 
399 Park Avenue
New York, New York  10022


Ladies and Gentlemen:

        I refer to the registration statement on Form S-4, Registration No. 
333-71203 (the "Registration Statement"), filed with the Securities and 
Exchange Commission under the Securities Act of 1933, as amended (the "Act"), 
pursuant to which Armco Inc., an Ohio corporation (the "Company"), is 
registering $75,000,000 aggregate principal amount of 8 7/8% Senior Notes due 
2008 (the "Exchange Notes"), under an Indenture dated as of November 1, 1993 
between the Company and Star Bank, N.A., as trustee (the "Trustee"), as 
supplemented by Supplemental Indenture No. 1, dated as of November 1 1993, 
and Supplemental Indenture No. 2, dated as of December 15, 1998 (the 
"Indenture"), to be issued in exchange for $75,000,000 aggregate principal 
amount of the Company's outstanding 8 7/8% Senior Notes due 2008 (the 
"Exchange Offer").  The terms and conditions of the Exchange Notes and the 
Exchange Offer are as set forth in the Registration Statement and the 
prospectus (the "Prospectus") contained therein.

        I have examined originals or copies, certified or otherwise 
identified to my satisfaction, of the Registration Statement, the Indenture, 
the form of Exchange Notes set forth in the Indenture, and such corporate 
records, agreements, documents and other instruments, and such certificates 
or comparable documents of public officials and of officers and 
representatives of the Company, and have made such inquiries of such officers 
and representatives as I have deemed relevant and necessary as a basis for 
the opinions hereinafter set forth.

        Based upon and subject to the foregoing, I am of the opinion that the 
Exchange Notes have been duly authorized by the Company.

        The foregoing opinion is limited to the laws of the State of Ohio and 
I express no opinion herein concerning the laws of any other jurisdiction.





        I hereby consent to the filing of this opinion as an exhibit to the 
Registration Statement and/or as an attachment to your opinion being filed as 
an exhibit to the Registration Statement (and in this regard I consent to 
your reliance on this opinion) and to be named under the caption "Legal 
Matters" in the Prospectus forming part of the Registration Statement.  In 
giving this consent, I do not thereby admit that I am within the category of 
persons whose consent is required under Section 7 of the Act or the rules and 
regulations of the Securities and Exchange Commission thereunder.

                                                Very truly yours,

                                                /s/ Gary R. Hildreth

                                                Gary R. Hildreth
                                                General Counsel