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EXHIBIT 99.1

CERTIFICATION PURSUANT TO 18 U.S.C. 1350, AS ADOPTED PURSUANT
TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2002 of Robert Half International Inc. (the "Form 10-Q"), I, Harold M. Messmer, Jr., Chief Executive Officer of Robert Half International Inc., certify, pursuant to 18 U.S.C.  1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1.    The Form 10-Q 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 Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Robert Half International Inc.

November 12, 2002 /s/ Harold M. Messmer, Jr. Harold M. Messmer, Jr.
Chief Executive Officer
Robert Half International Inc.

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EXHIBIT 99.1

CERTIFICATION PURSUANT TO 18 U.S.C. 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002