**EXHIBIT 15.1**   **LETTER RE: UNAUDITED INTERIM FINANCIAL INFORMATION**

Board of Directors and ShareholdersSTERISCorporation

            We are aware of the incorporation by reference in the following Registration Statements and related Prospectuses of our reportdated July 18, 2002, relating to the unaudited consolidated interim financial statements of STERIS Corporation and Subsidiaries that are included in its Form 10-Q for the quarter ended June 30, 2002: 

|   | **Registration****Number** |   | **Description**                                                                                                                                                                                                       |
|--------|----------------------------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-91302                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Mark. D. McGinley                                                                                           |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-40058                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Les C. Vinney                                                                                               |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-40082                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Laurie Brlas and the Nonqualified Stock Option Agreement between STERIS Corporation and David L.Crandall    |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-65155                  |   | Form S-8 Registration Statement — STERIS Corporation 1998 Long Term Incentive Compensation Plan                                                                                                                  |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-55839                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and John Masefield and the Nonqualified Stock Option Agreement between STERIS Corporation and Thomas J.DeAngelo |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-32005                  |   | Form S-8 Registration Statement — STERIS Corporation 1997 Stock Option Plan                                                                                                                                      |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-06529                  |   | Form S-3 Registration Statement — STERIS Corporation                                                                                                                                                             |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-01610                  |   | Post-effective Amendment to Form S-4 on Form S-8 — STERIS Corporation                                                                                                                                            |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 33-91444                   |   | Form S-8 Registration Statement — STERIS Corporation 1994 Equity Compensation Plan                                                                                                                               |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 33-91442                   |   | Form S-8 Registration Statement — STERIS Corporation 1994 Nonemployee Directors Equity Compensation Plan                                                                                                         |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 33-55976                   |   | Form S-8 Registration Statement — STERIS Corporation 401(k) Plan                                                                                                                                                 |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 33-55258                   |   | Form S-8 Registration — STERIS Corporation Amended and Restated Non-Qualified Stock Option                                                                                                                       |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-63770                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Charles L. Immel and Restricted Shares Agreement between STERIS Corporation and Charles L.Immel             |
|   |                       |   |                                                                                                                                                                                                                  |
|   | 333-63772                  |   | Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Thomas J. Magulski                                                                                          |
|   |                       |   |                                                                                                                                                                                                                  |

** **

 **Registration****Number** **Description**     333-63774 Form S-8 Registration Statement — Nonqualified Stock Option Agreement between STERIS Corporation and Peter A. Burke             /S/ ERNST & YOUNG LLP  Cleveland, Ohio August 13, 2002