Exhibit
  31.2

Certification
  of Principal Financial Officer

I, Mark Slaven, certify
  that:

|1. | I
      have reviewed this annual report on Form 10-K of 3Com Corporation;                                                                                                                                                                                                                                                        
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|2. | Based
      on my knowledge, this report does not contain any untrue statement of a
      material fact or omit to state a material fact necessary to make the statements
      made, in light of the circumstances under which such statements were made,
      not misleading with respect to the period covered by this report;
|3. | Based
      on my knowledge, the financial statements, and other financial information
      included in this report, fairly present in all material respects the financial
      condition, results of operations and cash flows of the registrant as of,
      and for, the periods presented in this report;                   
|4. | The
      registrants other certifying officer(s) and I are responsible for
      establishing and maintaining disclosure controls and procedures (as defined
      in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:                                                                                  
|   | (a)                                                                                                                                                                                                                                                                                                                               
|   | (b)                                                                                                                                                                                                                                                                                                                               
|   | (c)                                                                                                                                                                                                                                                                                                                               
|5. | The
      registrants other certifying officer(s) and I have disclosed, based
      on our most recent evaluation of internal control over financial reporting,
      to the registrants auditors and the audit committee of the registrants
      board of directors (or persons performing the equivalent functions):        
|   | (a)                                                                                                                                                                                                                                                                                                                               
|   | (b)                                                                                                                                                                                                                                                                                                                               

|Date: | August 1,
      2003 | /s/ MARK
      SLAVEN                                                                 
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|      |                      |                                                                                       
|      |                      | Mark Slaven
      Executive Vice President, Finance, and Chief
      Financial Officer

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