UNITED STATES


                       SECURITIES AND EXCHANGE COMMISSION


                             WASHINGTON, D.C. 20549


                                -----------------


                                  SCHEDULE 13G
                                (Amendment No. 1)

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934


             Information to be included in statements filed pursuant
           to Rules 13d-1(b), (c) and (d) and amendments thereto filed
                            pursuant to Rule 13d-2(b)

                                ----------------

                               LUMINEX CORPORATION
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                   55027E 10 2
                                 (Cusip Number)

                                December 31, 2001
             (Date of Event Which Requires Filing of this Statement)

                                -----------------

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

          [ ]  Rule 13d-1(b)

          [ ]  Rule 13d-1(c)

          [X]  Rule 13d-1(d)


The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.


The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                                Page 1 of 5 Pages




CUSIP No. 55027E 10 2             SCHEDULE 13G
                             (cover page continued)

1.   NAME OF REPORTING PERSON

                  G. Walter Loewenbaum

     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP *

                                           (A) [ ]
                                           (B) [ ]

3.   SEC USE ONLY

4.   CITIZENSHIP OR PLACE OF ORGANIZATION

                  United States

                             5.   SOLE VOTING POWER

                                  1,729,680(1)
NUMBER OF
SHARES                       6.   SHARED VOTING POWER
BENEFICIALLY
OWNED BY                          470,607(2)
EACH
REPORTING PERSON             7.   SOLE DISPOSITIVE POWER

                                  1,729,680(1)

                             8.   SHARED DISPOSITIVE POWER

                                  470,607(2)

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                  2,200,287

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*  [X]

                  1,301,600(3)

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

                  7.6 %

12.  TYPE OF REPORTING PERSON

                  IN

(1) 1,302,700 shares are held by Mr. Loewenbaum directly, 234,600 shares are
held by the Trustee for Mr. Loewenbaum's pension plan, 45,500 shares are held in
a trust of which Mr. Loewenbaum is the trustee and 146,880 are warrant shares
held by a trust for the benefit of Mr. Loewenbaum's children.

(2) 312,000 shares are held by a limited partnership for which Mr. And Mrs.
Loewenbaum serve as general partners and certain of the limited partners, 2,000
shares are held in a trust of which Mr. Loewenbaum is a trustee, 1,000 shares
are held by a limited partnership of which Mr. Loewenbaum has an indirect
interest, 145,607 are warrant shares and 10,000 shares of Common Stock subject
to vested and immediately exercisable stock options.

(3) These shares are held by Mrs. Loewenbaum. Mr. Loewenbaum disclaims any
beneficial ownership of these securities, and this report shall not be deemed an
admission that the reporting person is the beneficial owner of such securities
for this or any other purpose.

                                Page 2 of 5 Pages




                                  SCHEDULE 13G

ITEM 1(A).      NAME OF ISSUER:   Luminex Corporation

ITEM 1(B).      ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:

                12212 Technology Blvd., Austin, Texas 78727

ITEM 2(A).      NAME OF PERSON FILING:   G. Walter Loewenbaum

ITEM 2(B).      ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE:

                1708 Windsor, Austin, TX 78703

ITEM 2(C).      CITIZENSHIP:   United States (Texas)

ITEM 2(D).      TITLE OF CLASS OR SECURITIES:   Common Stock, $0.001 par value

ITEM 2(E).      CUSIP NUMBER:   55027E 10 2

ITEM 3.         IF THIS STATEMENT IS FILED PURSUANT TO RULE 13d-1(b) OR
                13d-2(b),

                (A)  [ ]  BROKER OR DEALER REGISTERED UNDER THE ACT

                (B)  [ ]  BANK AS DEFINED IN SECTION 3(A)(6) OF THE ACT

                (C)  [ ]  INSURANCE COMPANY AS DEFINED IN SECTION 3(A)(19) OF
                          THE ACT

                (D)  [ ]  INVESTMENT COMPANY REGISTERED UNDER SECTION 8 OF THE
                          INVESTMENT COMPANY ACT

                (E)  [ ]  INVESTMENT ADVISER REGISTERED UNDER SECTION 203 OF THE
                          INVESTMENT ADVISERS ACT OF 1940

                (F)  [ ]  EMPLOYEE BENEFIT PLAN, PENSION FUND WHICH IS SUBJECT
                          TO THE PROVISIONS OF THE EMPLOYEE RETIREMENT INCOME
                          SECURITY ACT OF 1974 OR ENDOWMENT FUND; SEE SECTIONS
                          240.13d-(B)(1)(II)(F)

                (G)  [ ]  PARENT HOLDING COMPANY, IN ACCORDANCE WITH SECTIONS
                          240.13d-1(b)(II)(G); SEE ITEM 7

                (H)  [ ]  GROUP, IN ACCORDANCE WITH SECTIONS
                          240.13d-1(b)(1)(II)(H)

ITEM 4.         OWNERSHIP:

(A) AMOUNT BENEFICIALLY OWNED:2,200,287 shares of which 1,302,700 shares are
held by Mr. Loewenbaum directly, 234,600 shares are held by the Trustee for Mr.
Loewenbaum's pension plan, 45,500 shares are held in a trust of which Mr.
Loewenbaum is the trustee and 146,880 are warrant shares held by a trust for the
benefit of Mr. Loewenbaum's children, 312,000 shares are held by a limited
partnership for which Mr. And Mrs. Loewenbaum serve as general partners and
certain of the limited partners, 2,000 shares are held in a trust of which Mr.
Loewenbaum is a trustee, 1,000 shares are held by a limited partnership of which
Mr. Loewenbaum has an indirect interest, 145,607 are warrant shares and 10,000
shares of Common Stock subject to vested and immediately exercisable stock
options.

         (B)    PERCENT OF CLASS:  7.6%


                                Page 3 of 5 Pages






                                  SCHEDULE 13G


                (C)  NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:

                     (I)   SOLE POWER TO VOTE OR TO DIRECT THE VOTE:

                                    1,729,680

                     (II)  SHARED POWER TO VOTE OR TO DIRECT THE VOTE:

                                    470,607

                     (III) SOLE POWER TO DISPOSE OR TO DIRECT THE DISPOSITION
                           OF:

                                    1,729,680

                     (IV)  SHARED POWER TO DISPOSE OR TO DIRECT THE DISPOSITION
                           OF:

                                    470,607


ITEM 5.         OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

                    IF THIS STATEMENT IS BEING FILED TO REPORT THE FACT THAT AS
                    OF THE DATE HEREOF THE REPORTING PERSON HAS CEASED TO BE
                    THE BENEFICIAL OWNER OF MORE THAN FIVE PERCENT OF THE CLASS
                    OF SECURITIES, CHECK THE FOLLOWING [ ].

                    Not applicable.

ITEM 6.         OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

                    Not applicable.

ITEM 7.         IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
                ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING
                COMPANY.

                    Not applicable.

ITEM 8.         IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

                    Not applicable.

ITEM 9.         NOTICE OF DISSOLUTION OF GROUP.

                    Not applicable.

ITEM 10.        CERTIFICATION.

                           By signing below I certify that, to the best of my
                knowledge and belief, the securities referred to above were not
                acquired and are not held for the purpose of or with the effect
                of changing or influencing the control of the issuer of the
                securities and were not acquired and are not held in connection
                with or as a participant in any transaction having that purpose
                or effect.


                                Page 4 of 5 Pages




                                  SCHEDULE 13G

                                    SIGNATURE

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.





                                                   /s/ G. Walter Loewenbaum
                                                 -------------------------------
                                                 G. Walter Loewenbaum

Date:  12 February 2002


                                Page 5 of 5 Pages