Exhibit 32.1


                            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 of Knight Transportation,  Inc.
(the  "Company") on Form 10-Q for the period ended  September 30, 2003, as filed
with the Securities and Exchange  Commission on the date hereof (the  "Report"),
I, Kevin P. Knight, Chief Executive 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) 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/ Kevin P. Knight
                                  -----------------------------------
                                  Kevin P. Knight
                                  Chief Executive Officer
                                  October 31, 2003

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