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                                                                       EXHIBIT 3

                     VOTING AGREEMENT AND IRREVOCABLE PROXY

            WHEREAS, pursuant to an Agreement and Plan of Merger (the "Merger
Agreement") dated of even date herewith among ICO, Inc., a Texas corporation
("ICO"), ICO Acquisition of Indiana, Inc., an Indiana corporation and
wholly-owned subsidiary of ICO ('Sub"), Polymer Service of Indiana, Inc., an
Indiana corporation ("PSI") and the shareholders of PSI (including the
undersigned), PSI is to be merged with and into Sub and become a wholly-owned
subsidiary of ICO (the "Merger"), and, in connection with the Merger, the
undersigned shareholder of PSI will receive, among other consideration, certain
shares of the Common Stock, no par value, of ICO (the "Common Stock") in
exchange for the shares of common stock of PSI owned by him at the effective
time of the Merger; and

            WHEREAS, to induce ICO and Sub to enter the Merger Agreement, the
undersigned wishes to enter this agreement to grant the Chairman of the Board or
the President of ICO or, either of them, as designated officers of ICO, as his
proxy with respect to the voting of shares of Common Stock owned by the
undersigned in the manner set forth below;

            NOW THEREFORE, in consideration of the foregoing, the undersigned
hereby agrees as follows:

      1. Agreement to Vote Shares. The undersigned hereby agrees that, except
with respect to any merger, sale of all or substantially all of the assets or
liquidation or dissolution of the Company, or any transaction having the same
effect, with respect to all matters hereafter submitted to a vote or consent of
the shareholders of ICO, he will vote all shares of Common Stock received by him
pursuant to the Merger Agreement at the direction of the Chairman of the Board
or the President of ICO, if so requested by either such person.

      2. Grant of Proxy. The undersigned hereby revokes any prior proxies and
appoints the Chairman of the Board and the President of ICO, or either of them,
with or without the other, proxies, with full power of substitution, to vote in
their sole discretion all shares of Common Stock that the undersigned is
entitled to vote at any special or annual meeting of the shareholders of ICO (or
any postponement or adjournment thereof), cumulatively or otherwise, on any
matters on which the shareholders are entitled to vote. In addition, such
proxies are granted the power to execute written consents with respect to any
matter to which they would be entitled to vote at a meeting of the shareholders
of ICO as set forth above.

      3. Representations and Warranties. The undersigned represents, warrants
and acknowledges that he has full power and authority to execute this Voting
Agreement and Irrevocable Proxy ("Agreement"), and that this Agreement is
binding and enforceable against him in accordance with its terms.

      4. Proxy Irrevocable. THE UNDERSIGNED AGREES AND ACKNOWLEDGES THAT, AS A
SHAREHOLDER OF PSI, HE WILL RECEIVE SUBSTANTIAL CONSIDERATION IN CONNECTION WITH
THE MERGER, AND THAT THIS AGREEMENT IS EXECUTED BY THE UNDERSIGNED IN
CONSIDERATION FOR EXECUTION OF THE MERGER AGREEMENT BY ICO AND SUB, AND THAT THE
PROXY GRANTED IN PARAGRAPH 2 HEREOF SHALL BE DEEMED TO BE COUPLED
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                                                                       EXHIBIT 3


WITH AN INTEREST AND IS IRREVOCABLE. THE UNDERSIGNED FURTHER AGREES THAT HE WILL
NOT GRANT ANY PROXY OR PROXIES INCONSISTENT WITH THIS AGREEMENT.

      5. Termination Transferability of Shares. The provisions of this Agreement
shall apply to the Common Stock for as long as the Common Stock is owned by the
undersigned or any person or entity related or affiliated to the undersigned or
ten (10) years from the date hereof, whichever is shorter. The undersigned will
not transfer any shares of Common Stock received by him in the Merger to a
person or entity related or affiliated with the undersigned unless the
transferee agrees that the shares transferred will remain subject to this
Agreement. ICO shall have the right to refuse to transfer, and to instruct its
transfer agent to refuse to transfer, any of the Common Stock unless the
foregoing provisions have been satisfied.

            IN WITNESS WHEREOF, the undersigned has executed this Agreement as
of this 19 day of July 1996.


                                          /s/ Joe Moore
                                          ---------------------------------
                                          (Signature)


                                          Joe Moore
                                          ---------------------------------
                                          (Name)

Agreed to and Accepted by ICO


By:    /s/ Jon C. Biro
       -----------------------
Name:  Jon C. Biro
Title: Treasurer
Date:  July 18, 1996