Exhibit 32.1

CERTIFICATION OF CEO PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

The certification set forth below is being submitted in connection with this quarterly report on Form 10-Q (the Report) for the purpose of complying with Rule 13a-14(b) or Rule 15d-14(b) of the Securities Exchange Act of 1934 (the Exchange Act) and Section 1350 of Chapter 63 of Title 18 of the United States Code.

I, Amnon Landan, the Chief Executive Officer of Mercury Interactive Corporation, certify that, to the best of my knowledge:

(1) the Report fully complies with the requirements of Section 13(a) or 15(d) of the Exchange Act; and

(2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of Mercury Interactive Corporation.

Date: August 14, 2003

/s/ Amnon Landan

Amnon Landan

President, Chief Executive Officer and Chairman of the Board