|Sopheon plc Annual Report on Form
      20-F | Exhibit 12.1
|-------------------------------------------- | ------------

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CERTIFICATION

I, Andrew Lloyd Michuda, Chief
Executive Officer of Sopheon plc, certify that:

| | 1. | I
      have reviewed this annual report on Form 20-F of Sopheon plc;                                                                                                                                                                                                                                                                   
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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 company
      as of, and for the periods presented in this report.                              
| |    |                                                                                                                                                                                                                                                                                                                                         
| | 4. | The
      company's other certifying officer 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 company and have:                                                                                                 
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| |    | (a)                                                                                                                                                                                                                                                                                                                                     
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| |    | (b)                                                                                                                                                                                                                                                                                                                                     
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| |    | (c)                                                                                                                                                                                                                                                                                                                                     
| |    |                                                                                                                                                                                                                                                                                                                                         
| | 5. | The
      company's other certifying officer and I have disclosed, based on our most
      recent evaluation of internal control over financial reporting, to the
      company's auditors and the audit committee of the company's board of
      directors (or persons performing the equivalent functions):                          
| |    |                                                                                                                                                                                                                                                                                                                                         
| |    | (a)                                                                                                                                                                                                                                                                                                                                     
| |    |                                                                                                                                                                                                                                                                                                                                         
| |    | (b)                                                                                                                                                                                                                                                                                                                                     



By: /s/ Andrew
        Lloyd MichudaName: Andrew Lloyd Michuda 
        Title: Chief Executive OfficerDate: July 13, 2004