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Exhibit 12.1

CERTIFICATION

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

| 1. | I have reviewed this annual report onForm 20-F of Sopheon plc;                                                                                                                                                                                                                                         |
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| 2. | Based on my knowledge, this report doesnot contain any untrue statement of a material fact or omit to state a materialfact necessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the periodcovered by this report; |
| 3. | Based on my knowledge, the financialstatements, and other financial information included in this report fairlypresent in all material respects the financial condition, results of operationsand cash flows of the company as of, and for the periods presented in thisreport.                         |
| 4. | The company's other certifyingofficer and I are responsible for establishing and maintaining disclosurecontrols and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the company and have:                                                                                     |
|    | (a)                                                                                                                                                                                                                                                                                                    | designed such disclosure controls andprocedures, or caused such internal controls to be designed under oursupervision, to ensure that material information relating to the company,including its consolidated subsidiaries, is made known to us by others withinthose entities, particularly during the period in which this report is beingprepared; |
|    | (b)                                                                                                                                                                                                                                                                                                    | evaluated the effectiveness of thecompany's disclosure controls and procedures and presented in this report ourconclusions about the effectiveness of the disclosure controls and procedures,as of the end of the period covered by this report based on such evaluation; and |
|    | (c)                                                                                                                                                                                                                                                                                                    | disclosed in this report any change inthe company's internal control over financial reporting that occurred duringthe period covered by the report that has materially affected, or is reasonablylikely to materially affect, the company's internal control over financialreporting. |
| 5. | The company's other certifyingofficer and I have disclosed, based on our most recent evaluation of internalcontrol over financial reporting, to the company's auditors and the auditcommittee of the company's board of directors (or persons performing theequivalent functions):                     |
|    | (a)                                                                                                                                                                                                                                                                                                    | all significant deficiencies andmaterial weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect the company'sability to record, process, summarize and report financial information; and |
|    | (b)                                                                                                                                                                                                                                                                                                    | any fraud, whether or not material,that involves management or other employees who have a significant role in thecompany's internal control over financial reporting. |

 

|                            | By: /s/ AndrewLloyd MichudaName: Andrew Lloyd MichudaTitle: Chief Executive Officer |
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| Date: July 8, 2005

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