EXHIBIT 5.1


                               January 26, 1999


Inland Steel Industries, Inc.
30 West Monroe Street
Chicago, Illinois  60603


     Re:  Merger of RT Merger Sub, Inc., a wholly owned subsidiary of Inland
          Steel Industries, Inc., with and into Ryerson Tull, Inc.

Ladies and Gentlemen:
    
     We have acted as special counsel to Inland Steel Industries, Inc., a
Delaware corporation ("Inland"), in connection with the corporate proceedings
taken and to be taken relating to the merger of RT Merger Sub, Inc., a wholly
owned subsidiary of Inland, with and into Ryerson Tull, Inc. ("Ryerson Tull"),
with Ryerson Tull being the surviving corporation (the "Merger"), and conversion
of each share of Ryerson Tull Class A Common Stock, par value $1.00 per share
(including the associated preferred stock purchase rights issued pursuant to the
Rights Agreement, dated as of June 10, 1996, between Ryerson Tull and Harris
Trust and Savings Bank, as the Rights Agent), issued and outstanding at the
effective time of the Merger into 0.61 shares of common stock, par value $1.00
per share, of Inland ("Inland Common Stock") (including the associated preferred
stock purchase rights issued pursuant to the Rights Agreement, dated as of
November 25, 1997, between Inland and Harris Trust and Savings Bank, as the
Rights Agent, as amended). We have also participated in the preparation and
filing with the Securities and Exchange Commission under the Securities Act of
1933, as amended, of a registration statement on Form S-4 (the "Registration
Statement") relating to the Merger. In this connection, we have examined such
corporate and other records, instruments, certificates and documents as we
considered necessary to enable us to express this opinion.    

     Based on the foregoing, it is our opinion that the shares of Inland Common
Stock have been duly and validly authorized by all necessary action on the part 
of Inland and when issued pursuant to the terms of the Agreement and Plan of 
Merger, dated October 27, 1998, will be validly issued, fully paid and 
non-assessable by Inland.

     We consent to the filing of this opinion as an exhibit to the Registration
Statement and to the reference to us under the captions "The Merger Agreement 
and the Merger -- Material Federal Income Tax Considerations" and "Additional
Information -- Legal Matters" therein.

                              Very truly yours,


                              MAYER, BROWN & PLATT