EXHIBIT 32 SECTION 1350 CERTIFICATIONS Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the undersigned certifies that this periodic report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in this periodic report fairly presents, in all material respects, the financial condition and results of operations of Smithway Motor Xpress Corp. Date: March 28, 2006 /s/ G. Larry Owens ----------------------------------------------- G. Larry Owens President, Chief Executive Officer and Secretary Date: March 28, 2006 /s/ Douglas C. Sandvig ----------------------------------------------- Douglas C. Sandvig Senior Vice President, Chief Financial Officer and Treasurer