Exhibit 99.1


                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER
                       PURSUANT TO 18 U.S.C. SECTION 1350

In connection with the accompanying Amendment No. 1 to Quarterly Report on Form
10-Q/A of Ascential Software Corporation for the quarter ended June 30, 2002, I,
Peter Gyenes, Chief Executive Officer of Ascential Software Corporation, hereby
certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906
of the Sarbanes-Oxley Act of 2002, to the best of my knowledge and belief, that:

     (1) such Amendment No. 1 to Quarterly Report on Form 10-Q/A for the quarter
     ended June 30, 2002 fully complies with the requirements of Section 13(a)
     or 15(d) of the Securities Exchange Act of 1934; and

     (2) the information contained in such Amendment No. 1 to Quarterly Report
     on Form 10-Q/A for the quarter ended June 30, 2002, fairly presents, in all
     material respects, the financial condition and results of operations of
     Ascential Software Corporation.


                                             /s/ Peter Gyenes
                                             ------------------------------
                                             Peter Gyenes

August 27, 2002