EXHIBIT 15.1 LETTER RE: UNAUDITED INTERIM FINANCIAL INFORMATION

Board of Directors and ShareholdersSTERIS Corporation

We are aware of the incorporation by reference in the following Registration Statements and related Prospectuses of our report dated October 16,
2001, 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 September 30, 2001:





|RegistrationNumber |  | Description                                                                                                                                                                                                     |  | Filing Date    
|------------------ |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ---------------
|                  
|333-63770          |  | Form S-8 Registration Statement -- Nonqualified Stock Option

Agreement between STERIS Corporation and Charles L.Immel and Restricted Shares Agreement between STERISCorporation and Charles L. Immel           |  | June 25, 2001  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-63772          |  | Form S-8 Registration Statement -- Nonqualified Stock OptionAgreement between STERIS Corporation and Thomas J.Magulski                                                                                          |  | June 25, 2001  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-63774          |  | Form S-8 Registration Statement -- Nonqualified Stock OptionAgreement between STERIS Corporation and Peter A. Burke                                                                                             |  | June 25, 2001  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-40082          |  | Form S-8 Registration Statement -- Nonqualified Stock OptionAgreement between STERIS Corporation and Laurie Brlas andthe Nonqualified Stock Option Agreement between STERISCorporation and David L. Crandall    |  | June 26, 2000  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-40058          |  | Form S-8 Registration Statement -- Nonqualified Stock OptionAgreement between STERIS Corporation and Les C. Vinney                                                                                              |  | June 23, 2000  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-65155          |  | Form S-8 Registration Statement -- STERIS Corporation LongTerm Incentive Compensation Plan                                                                                                                      |  | October 1, 1998
|                   |  |                                                                                                                                                                                                                 |  |                
|333-55839          |  | Form S-8 Registration Statement -- Nonqualified Stock OptionAgreement between STERIS Corporation and John Masefieldand the Nonqualified Stock Option Agreement betweenSTERIS Corporation and Thomas J. DeAngelo |  | June 2, 1998   
|                   |  |                                                                                                                                                                                                                 |  |                
|333-32005          |  | Form S-8 Registration Statement -- STERIS Corporation 1997Stock Option Plan                                                                                                                                     |  | July 24, 1997  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-06529          |  | Form S-3 Registration Statement -- STERIS Corporation                                                                                                                                                           |  | June 21, 1996  
|                   |  |                                                                                                                                                                                                                 |  |                
|333-01610          |  | Post-effective Amendment to Form S-4 on Form S-8 -- STERIS Corporation                                                                                                                                          |  | May 16, 1996   
|                   |  |                                                                                                                                                                                                                 |  |                
|33-91444           |  | Form S-8 Registration Statement -- STERIS Corporation 1994Equity Compensation Plan                                                                                                                              |  | April 24, 1995 

|33-91442 | Form S-8 Registration Statement -- STERIS Corporation 1994Nonemployee Directors Equity Compensation Plan  |  | April 24, 1995       
|-------- | --------------------------------------------------------------------------------------------------------- |  | ---------------------
|         |                                                                                                           |  |                      
|33-55976 | Form S-8 Registration Statement -- STERIS Corporation401(k) Plan                                          |  | December 21, 1992    
|         |                                                                                                           |  |                      
|33-55258 | Form S-8 Registration Statement -- STERIS CorporationAmended and Restated Non-Qualified Stock Option Plan |  | December 4, 1992     
|         |                                                                                                           |  |                      
|         |                                                                                                           |  | /s/ Ernst & Young LLP



Cleveland, OhioNovember 8, 2001