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                                                                    EXHIBIT 5.1
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August 7, 2000


IDEXX Laboratories, Inc.
One IDEXX Drive
Westbrook, Maine  04092

    Re:  2000 Director Option Plan
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Ladies and Gentlemen:

   I am General Counsel to IDEXX Laboratories, Inc., a Delaware corporation (the
"Company").  In such capacity, I have assisted in the preparation of a
Registration Statement on Form S-8 (the "Registration Statement") to be filed
with the Securities and Exchange Commission relating to the registration of
200,000 shares of Common Stock, par value $.10 per share (the "Shares"), of the
Company, issuable under the Company's 2000 Director Option Plan (the "Plan").

   I have examined the Restated Certificate of Incorporation of the Company, as
amended, the Amended and Restated By-Laws of the Company, as amended, and
originals, or copies certified to my satisfaction, of all pertinent records of
the meetings of the directors and stockholders of the Company, the Registration
Statement and such other documents relating to the Company as I have deemed
material for purposes of this opinion.

   In my examination of the foregoing documents, I have assumed the genuineness
of all signatures and the authenticity of all documents submitted to me as
originals, the conformity to original documents of all documents submitted to me
as certified or photostatic copies, and the authenticity of the originals of
such latter documents.

   Based on the foregoing, I am of the opinion that the Company has duly
authorized for issuance the Shares, as described in the Registration Statement,
and the Shares, when issued in accordance with the terms of the Plan, will be
legally issued, fully paid and nonassessable.

   I hereby consent to the filing of this opinion with the Securities and
Exchange Commission in connection with the Registration Statements.

                                                   Very truly yours,

                                                   /s/ Conan R. Deady
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                                                   Conan R. Deady
                                                   General Counsel