Exhibit 99.3

COGNOS INCORPORATED

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 of Cognos Incorporated (the “Company”) on Form 10-Q for the period ended November 30, 2002 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Tom Manley, Senior Vice President Finance & Administration and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. section 1350, as adopted pursuant to section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

    (1)        The Report fully complies with the requirements of section 13(a) or15(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.

January 13, 2003	/s/ Tom Manley
Date	Tom Manley Senior Vice President, Finance & Administration and Chief Financial Officer (Principal Financial Officer and Chief Accounting Officer)

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