EXHIBIT 5.1

Exhibit 5.1

IDEXX IDEXX Laboratories, Inc.
One IDEXX Drive, Westbrook, Maine 04092 USA
Telephone 207-856-0300
August 30, 1996 Facsimile 207-856-0346
Telex 9103807069

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

Re: 1991 Stock Option Plan

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 975,000
shares of Common Stock, par value $.10 per share (the "Shares"),
of the Company, issuable upon exercise of options to be granted
under the Company's 1991 Stock 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 covered by the
Registration Statement to be issued under the Plans, 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 Statement.

Very truly yours,

/s/ Richard B. Thorp
Richard B. Thorp
General Counsel