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EXHIBIT 5.1






                                 August 31, 2001




i-STAT Corporation
104 Windsor Center Drive
East Windsor, NJ  08520

     Re:      i-STAT Corporation Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel for i-STAT Corporation, a Delaware corporation
(the "Company"), in connection with the preparation and filing with the
Securities and Exchange Commission (the "Commission") of a registration
statement on Form S-3 (the "Registration Statement"), relating to 6,488,195
shares (the "Shares") of common stock, par value $.15 per share of the Company
which may be offered from time to time by the persons named in the Registration
Statement as the selling stockholders. You have requested that we furnish our
opinion as to the matters set forth below.

For purposes of rendering this opinion, we have examined the Restated
Certificate of Incorporation of the Company, as amended, including the
Certificate of Designations of Series C Preferred Stock of the Company (the
"Certificate of Designations"), the Bylaws of the Company the warrants to
purchase shares of the company's common stock described in the Registration
Statement (the "Warrants"), and the originals, or copies certified or otherwise
identified to our satisfaction, of records of  corporate proceedings of the
Company as made available to us by the Company,  certificates of public
officials and of representatives of the Company, and  such other documents and
records as we deemed necessary. In such examination  we have assumed the
genuineness of all signatures, the authenticity of all  corporate records and
other documents submitted to us as originals and the  conformity to original
documents of documents submitted to us as certified or  photostatic copies.

                  Based upon our examination as aforesaid, and in reliance upon
our examination of such questions of law as we deemed relevant under the
circumstances, we are of the opinion that 1,480,000 of the Shares are validly
issued, fully paid and nonassessable and that the balance of the Shares, when
issues by the Company in accordance with the terms of the Certificate of
Designation and the Warrants, as the case may be, will be validly issued,
nonassessable.
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August 31, 2001
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                  We hereby consent to the filing of this opinion of counsel as
Exhibit 5.1 to the Registration Statement and to the reference to us contained
in the prospectus which forms part of the Registration Statement under the
heading "Legal Matters." In giving the foregoing consent, we do not thereby
admit that we belong to the category of persons whose consent is required under
Section 7 of the Securities Act of 1933, as amended, or the rules and
regulations promulgated by the Commission thereunder.

                                     Very truly yours,


                                     PAUL, HASTINGS, JANOFSKY & WALKER LLP