EXHIBIT 5.1

October 14, 2003

Informatica Corporation
2100 Seaport Boulevard
Redwood City, CA 94063

     RE: REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

          We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Informatica Corporation, a Delaware corporation (the “Registrant” or “you”), with the Securities and Exchange Commission on or about the date hereof, in connection with the registration under the Securities Act of 1933, as amended, of an aggregate of 6,162,108 shares of your Common Stock, $.001 par value (the “Shares”), reserved for issuance pursuant to the 1999 Stock Incentive Plan, as amended, the 1999 Employee Stock Purchase Plan, as amended, and the Striva Corporation 2000 Stock Plan (together, the “Plans”). As your legal counsel, we have reviewed the actions proposed to be taken by you in connection with the issuance and sale of the Shares to be issued under the Plan.

          It is our opinion that the Shares, when issued and sold in the manner referred to in the Plans and pursuant to the agreements which accompany the Plans, will be legally and validly issued, fully paid and nonassessable.

          We consent to the use of this opinion as an exhibit to the Registration Statement and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

Very truly yours,

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation

/s/ Wilson Sonsini Goodrich & Rosati