##### 



Exhibit 12.1

CERTIFICATION

I, Prof. Dr. Henning Kagermann, certify that:



|   |                                                                                                                                                                                                                                                                                                                                             
|-- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|1. | I have reviewed this annual report on
    Form 20-F of SAP AG;                                                                                                                                                                                                                                                                              
|  
|2. | Based on my knowledge, this annual 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
    annual report;
|  
|3. | Based on my knowledge, the financial statements,
    and other financial information included in this annual 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 annual report;                       
|  
|4. | The registrants other certifying officers
    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) | Designed such disclosure controls and procedures,
    or caused such disclosure controls and procedures to be designed
    under our supervision, to ensure that material information
    relating to the registrant, including its consolidated
    subsidiaries, is made known to us by others within those
    entities, particularly during the period in which this annual
    report is being prepared;
|
| | b) | [Reserved];                                                                                                                                                                                                                                                                                                                                                                                                  
|
| | c) | Evaluated the effectiveness of the
    registrants disclosure controls and procedures and
    presented in this annual report our conclusions about the
    effectiveness of the disclosure controls and procedures, as of
    the end of the period covered by this annual report based on
    such evaluation; and                                                                                        



| |    |                                                                                                                                                                                                                                                                                                                                      
| | -- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | d) | Disclosed in this annual report any change in the
    registrants internal control over financial reporting that
    occurred during the period covered by the annual report that has
    materially affected, or is reasonably likely to materially
    affect, the registrants internal control over financial
    reporting; and



|   |                                                                                                                                                                                                                                                                                                                
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|5. | The registrants other certifying officers
    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
    registrants board of directors (or persons performing the
    equivalent function):



| |    |                                                                                                                                                                                                                                                                                          
| | -- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | a) | All significant deficiencies and material
    weaknesses in the design or operation of internal control over
    financial reporting which are reasonably likely to adversely
    affect the registrants ability 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 the
    registrants internal control over financial reporting.                                                                                                       

Dated March 23, 2004



| |                                  
| | ---------------------------------
| | /s/ HENNING KAGERMANN            
| |                                  
| | Name: Prof. Dr. Henning Kagermann
| | Title: Chief Executive Officer