Filed Pursuant to Rule 424(b)(7)
Registration No. 333-135208

PROSPECTUS SUPPLEMENT NO. 4 DATED SEPTEMBER 21, 2006
(To Prospectus dated June 21, 2006)

INFORMATICA CORPORATION

$230,000,000

3% Convertible Senior Notes due 2026 and
the Common Stock Issuable Upon Conversion of the Notes

          This prospectus supplement supplements information contained in the prospectus dated June 21, 2006 of Informatica Corporation, as previously supplemented by prospectus supplement dated June 27, 2006, prospectus supplement no. 2 dated July 21, 2006 and prospectus supplement no. 3 dated August 21, 2006 (as so supplemented, the “prospectus”), relating to the offer and sale from time to time by certain selling security holders of our 3% Convertible Senior Notes due 2026, which are referred to as the “notes,” and the common stock issuable upon conversion of the notes. We will not receive any proceeds from the sale of the notes or the common stock issuable upon conversion of the notes by the selling security holders.

          This prospectus supplement should be read in conjunction with, and may not be delivered or utilized without, the prospectus. This prospectus supplement is qualified by reference to the prospectus, except to the extent that the information in this prospectus supplement supersedes the information contained in the prospectus.

The date of this prospectus supplement is September 21, 2006

SELLING SECURITY HOLDERS

          The table below supplements or amends the table of selling security holders beginning on page 57 of the prospectus dated June 21, 2006. Where the name of a selling security holder identified in the table below also appears in the table in the prospectus, the information set forth in the table below regarding that selling security holder supersedes the information in the prospectus. This information was furnished to us by the selling security holders listed below on or before September 19, 2006. Because the selling security holders may offer, pursuant to this prospectus, all or some portion of the notes or common stock listed below, no estimate can be given as to the amount of notes or common stock that will be held by the selling security holders upon consummation of any sales. In addition, the selling security holders listed in the table may have sold, transferred or otherwise disposed of, in transactions exempt from the registration requirements of the Securities Act, some or all of their notes since the date as of which the information in the table is presented. We are not updating any information with respect to any other selling security holder set forth in the prospectus dated June 21, 2006, other than with respect to the holders set forth below.

Principal

Amount at

Maturity of

Shares of

Percentage of

Notes

Common

Common

Conversion

Beneficially

Stock Owned

Stock

Shares

Owned That

Percentage of

prior to the

Outstanding

Offered

Name

May Be Sold

Notes Outstanding

Offering (1)

(2)

Hereby

Lehman Brothers Inc.

$

500,000

*

25,000

*

25,000

PBGC Maintenance

$

40,000

*

2,000

*

2,000

Royal Bank of Canada

$

7,000,000

3.04

%

350,000

*

350,000