EXHIBIT 5.1
June 23, 2000

STERIS Corporation
5960 Heisley Road
Mentor, Ohio 44060

     Re:  STERIS Corporation Form S-8 Registration Statement --
          Nonqualified Stock Option Agreements between STERIS
          Corporation and Les C. Vinney

Ladies and Gentlemen:

     STERIS Corporation ("STERIS") is filing with the Securities and Exchange
Commission a Registration Statement on Form S-8 (the "Registration Statement")
for the registration, under the Securities Act of 1933, as amended, of 90,000
Common Shares, without par value, of STERIS ("STERIS Common Shares") to be
issued from time to time pursuant to the terms of a Nonqualified Stock Option
Agreement between STERIS and Les C. Vinney (the "Agreement").

     Item 601 of Regulation S-K and the instructions to Form S-8 require that an
opinion of counsel concerning the legality of the securities to be registered be
filed as an exhibit to a Form S-8 registration statement if the securities are
original issue shares.  This opinion is provided in satisfaction of that
requirement as it relates to the Registration Statement.

     In rendering this opinion, we have examined the following:

          A.  A copy of STERIS's current Amended Articles of Incorporation and
     Amended Regulations.

          B.  The records of the proceedings incorporating STERIS under the laws
     of the State of Ohio, records of other proceedings and public officials
     concerning the present status of STERIS as a corporation, and records of
     the proceedings of STERIS's Board of Directors and shareholders concerning
     authorization of STERIS Common Shares and approval of the Agreement.

     We have examined such other records and documents, and obtained such other
information, as we have deemed advisable in order to render this opinion.

     As a result of the foregoing, we are of the opinion that:

          (1) STERIS is a corporation validly organized and existing and in good
     standing under the laws of the State of Ohio.

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          (2) STERIS is authorized to issue 300,000,000 Common Shares, of which
     67,527,075 were issued and outstanding as of March 31, 2000.  When issued,
     the STERIS Common Shares that are the subject of the Registration Statement
     will be legally issued, fully paid, and non-assessable.

     We hereby consent to the use and filing of this opinion in connection with
the Registration Statement.

                              Very truly yours,



                              Thompson Hine & Flory LLP

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