**Exhibit 31.1**

 

**CERTIFICATIONS**

 

I, Robert K. Weiler, certify that:

 

1.                                       I have reviewed this quarterly report on Form 10-Qof Phase Forward Incorporated;

 

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.                                       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(s) and I are responsible for establishingand maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the registrant and have:

 

a)                                      Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our 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)                                     [Paragraph omitted in accordance with SECtransition instructions contained in SEC Releases No. 34-47986, 34-49313and 34-52492];

 

c)                                      Evaluated the effectiveness of theregistrant’s disclosure 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)                                     Disclosedin this report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter (theregistrant’s fourth fiscal quarter in the case of an annual report)that hasmaterially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and

 

5.                                       The registrant’s other certifyingofficers and I have disclosed, based on our most recent evaluation of internalcontrols over financial reporting, to the registrant’s auditors and the auditcommittee of the registrant’s board of directors (or persons performing theequivalent functions):

 

a)                                      All significant deficiencies and materialweaknesses in the design or operation of internal controls over financialreporting which are reasonably likely to adversely affect the registrant’sability to record, process, summarize and report financial information; and

 

b)                                     Anyfraud, whether or not material, that involves management or other employees whohave a significant role in the registrant’s internal controls over financialreporting.

 

Date:  November 14, 2005

 
|     | /s/ Robert  K. Weiler      |   |
|----------|----------------------------|--------|
| * * | Robert K. Weiler           |
|     |                       |
| * * | *Chief  Executive Officer* |

 

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