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 Luminex Corporation (the "Company")
on Form 10-Q for the period ended March 31, 2005, as filed with the Securities
and Exchange Commission on the date hereof (the "Report"), I, Patrick J.
Balthrop, President and 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:

      (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/ PATRICK J. BALTHROP
- -------------------------------------
Patrick J. Balthrop
President and Chief Executive Officer
May 10, 2005