##### 



Exhibit 31.1

CERTIFICATIONS



|                               |                                                                                                                                                                                                                                                                                                                                  
|------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|I, David DeWalt, certify that:
|                              
|                               | 1. I have reviewed this quarterly report on Form 10-Q of Documentum,
Inc.;                                                                                                                                                                                                                                                       
|                              
|                               | 2. Based on my knowledge, this quarterly 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 quarterly report;
|                              
|                               | 3. Based on my knowledge, the financial statements, and other financial
information included in this quarterly 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 quarterly 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 quarterly report is
being prepared;
|
| | b. evaluated the effectiveness of the registrants disclosure
controls and procedures and presented in this report our conclusions 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 changes in the registrants internal
control over financial reporting that occurred during the registrants most
recent fiscal quarter (the registrants fourth fiscal quarter by the case
of an annual report) that has materially affected, or is reasonably likely
to materially affect, the registrants internal control over financial
reporting;    



| |                                                                                                                                                                                                                                                                                                    
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | 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 the
registrants board of directors (or persons performing the equivalent
functions):



| |                                                                                                                                                                                                                                                                              
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | a. all significant deficiencies and material weaknesses in the design
or operation of internal controls 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
controls over financial reporting.                                                                                               

| |  |  |     |                                      
| |  |  | --- | -------------------------------------
| |  |  | By: | /s/ DAVID DEWALT                     
| |  |  |     | David DeWalt                         
| |  |  |     | President and Chief Executive Officer
| |  |  |     | (Principal Executive Officer)        

Date: August 14, 2003

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