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 Smithway Motor Xpress Corp. (the
"Company") on Form 10-Q for the period ended March 31, 2004, as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, G.
Larry Owens, 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/ G. Larry Owens
                                               --------------------------------
                                               G. Larry Owens
                                               Chief Executive Officer
                                               May 13, 2004