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Exhibit 31.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER
PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 I, Sohaib Abbasi, certify that:  1.
    I have reviewed this annual report on Form 10-K of Informatica Corporation;  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 officer 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)) and internal control over financial reporting (as defined in Exchange Act Rules
13a-15 (f) and 15d-15(f)) for the registrant and we 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.
    Designed such internal control over financial reporting, or caused such
internal control over financial reporting to be designed under our supervision, to
provide reasonable assurance regarding the reliability of financial reporting and
the preparation of financial statements for external purposes in accordance with
generally accepted accounting principles;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; andd.
    Disclosed in this annual report any change in the registrants internal
control over financial reporting that occurred during the registrants most recent
fiscal year 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 officer 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
functions):  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; andb.
    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. /s/ SOHAIB ABBASI
Sohaib Abbasi
Chief Executive Officer and President
 Dated: March 7, 2005