**Exhibit 31.1**

**CERTIFICATE OF THE CHIEF EXECUTIVE OFFICER**

I, theChief Executive Officer of Witness Systems, Inc. (the “registrant”),certify that:

1.             Ihave reviewed this report on Form 10-Q of the registrant for the quarterended March 31, 2007;

2.             Basedon my knowledge, this report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make the statementsmade, in light of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

3.             Basedon my knowledge, the financial statements, and other financial informationincluded in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, andfor, the periods presented in this report;

4.             Theregistrant’s other certifying officer and I are responsible for establishingand maintaining disclosure controls and procedures (as defined in Exchange ActRules 13a-15(e) and 15d-15(e)) and internal control over financialreporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f))  for the registrant and have:

(a)   designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designed underour supervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known to us byothers within those entities, particularly during the period in which thisreport is being prepared;

(b)   Designed such internal control overfinancial reporting, or caused such internal control over financial reportingto be designed under our supervision, to provide reasonable assurance regardingthe reliability of financial reporting and the preparation of financialstatements for external purposes in accordance with generally acceptedaccounting principles;

(c)   evaluated the effectiveness of theregistrant’s disclosures controls and procedures and presented in this reportour conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

(d)   disclosed in this report any change inthe registrant’s internal control over financial reporting that occurred duringthe registrant’s most recent fiscal quarter that has materially affected, or isreasonably likely to materially affect, the registrant’s internal control overfinancial reporting.

5.             Theregistrant’s other certifying officer and I have disclosed, based on our mostrecent evaluation of internal control over financial reporting, to theregistrant’s auditors and the audit committee of the registrant’s board ofdirectors:

(a)   all significant deficiencies andmaterial weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect theregistrant’s ability to record, process, summarize and report financialinformation; and

(b)   any fraud, whether or not material,that involves management or other employees who have a significant role in theregistrant’s internal controls over financial reporting.
| Dated: May 8, 2007 |   |   |
|-------------------------|--------|--------|
|                    |   |   |
|                    |   | BY:    | /s/  NICHOLAS DISCOMBE |   |
|                    |   |   | Nicholas Discombe |
|                    |   |   | *Chief Executive Officer* |

 

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