Open Text (OTEX) 10-Q 2003 Q3 Quarterly report

Exhibit 99.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED

PURSUANT TO SECTION 906

OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Open Text Corporation (the “Company”) for the quarter ended March 31, 2003 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, P. Thomas Jenkins, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. (S) 1350, as adopted pursuant to (S) 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

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

A signed original of this written statement required by Section 906 has been provided to Open Text Corporation and will be retained by Open Text Corporation and furnished to the Securities and Exchange Commission or its staff upon request.

/s/    P. THOMAS JENKINS         

P. Thomas Jenkins
Chief Executive Officer

Dated: May 14, 2003