<PAGE>
                                                                    EXHIBIT 99.1


      CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER
                      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 Current Report on Form 8-K of Nabors Industries Ltd. (the
"Company") as filed with the Securities and Exchange Commission on the date
hereof (the "Report"), Eugene M. Isenberg, as Chief Executive Officer of the
Company, and Bruce P. Koch, as Chief Financial Officer of the Company, each
hereby certifies, 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 his
knowledge:

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


      /s/ Eugene M. Isenberg
------------------------------------
Name:  Eugene M. Isenberg
Title: Chief Executive Officer
Date:  August 20, 2002


      /s/ Bruce P. Koch
------------------------------------
Name:  Bruce P. Koch
Title: Chief Financial Officer
Date:  August 20, 2002

This certification accompanies the Report pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the
Sarbanes-Oxley Act of 2002, be deemed filed by the Company for purposes of
Section 18 of the Securities Exchange Act of 1934, as amended.


