Exhibit 5.1



October 28, 2003

Fisher Scientific International Inc.
One Liberty Lane
Hampton, New Hampshire  03842


                      REGISTRATION STATEMENT ON FORM S-3 OF
                      FISHER SCIENTIFIC INTERNATIONAL INC.

Ladies and Gentlemen:

      We have acted as special counsel to Fisher Scientific International Inc.,
a Delaware corporation (the "Company"), in connection with the preparation and
filing with the Securities and Exchange Commission (the "Commission") under the
Securities Act of 1933, as amended (the "Securities Act"), of the Registration
Statement on Form S-3 of the Company (the "Registration Statement") relating to
the resale by certain selling securityholders of (a) up to $300,000,000
aggregate principal amount of the Company's 2.50% Senior Convertible Notes due
October 1, 2023 (the "Notes") and (b) such indeterminate number of shares of the
Company's common stock, par value $0.01 per share (the "Shares"), as may be
issuable upon conversion of the Notes. The Notes were issued under an indenture
dated as of July 7, 2003 (the "Indenture"), between the Company and J.P. Morgan
Trust Company, N.A., as trustee (the "Trustee").

      In connection with this opinion, we have examined the form of the Notes
and the Indenture. We also have examined originals or certified, conformed or
reproduction copies of such agreements, instruments, documents and records of
the Company, such certificates of public officials, and such other documents,
and have made such investigations of law, as we have deemed necessary or
appropriate for the purposes of the opinions expressed below. In all such
examinations, we have assumed the legal capacity of all natural persons
executing documents, the genuineness of all signatures on original or certified
copies, the authenticity of all original or certified copies and the conformity
to original or certified documents of all copies submitted to us as conformed or
reproduction copies. We have relied as to factual matters upon, and have assumed
the accuracy of, the statements made in the certificates of officers of the
Company delivered to us, and

Fisher Scientific International Inc.        2                   October 28, 2003


certificates and other statements or information of or from public officials and
officers and representatives of the Company.

      In rendering the opinions expressed below, we have assumed that (a) the
Trustee had the power and authority to enter into, and has the power and
authority to perform its obligations under, the Indenture, (b) the Indenture has
been duly authorized, executed and delivered by the Trustee and is valid,
legally binding and enforceable against the Trustee in accordance with its terms
and (c) the Notes have been duly authenticated by the Trustee in the manner
provided in the Indenture.

      Based on the foregoing, and subject to the limitations, qualifications and
assumptions set forth herein, we are of the opinion that:

      1.    The Notes have been duly authorized and executed by the Company and
            constitute valid and binding obligations of the Company, enforceable
            against the Company in accordance with their terms.

      2.    The Shares issuable upon conversion of the Notes at the initial
            conversion rate have been duly authorized and reserved for issuance
            upon such conversion by all necessary corporate action on the part
            of the Company, and such Shares, when issued upon such conversion in
            accordance with the terms of the Notes and the Indenture, will be
            validly issued, fully paid and non-assessable.

      The opinions expressed above are limited to the laws of the State of New
York and the General Corporation Law of the State of Delaware, including the
applicable provisions of the Delaware Constitution and the reported cases
interpreting those laws, in each case as currently in effect, and we do not
express any opinion herein concerning any other laws.

      The opinions expressed above are limited by and subject to the effects of
(i) bankruptcy, insolvency, fraudulent conveyance, fraudulent transfer,
reorganization, moratorium or other similar laws relating to or affecting
enforcement of creditors' rights or remedies generally, (ii) general principles
of equity, whether such principles are considered in a proceeding at law or in
equity, (iii) an implied covenant of good faith, reasonableness and fair
dealing, and standards of materiality and (iv) limitations with respect to
enforceability of provisions providing for indemnification or contribution
arising under applicable law (including court decisions) or public policy.

      We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our firm under the heading "Legal
Matters" in the prospectus included in the Registration Statement. In giving
such consent, we do not thereby concede that we are within the category of
persons whose consent is required

Fisher Scientific International Inc.        3                   October 28, 2003

under Section 7 of the Securities Act or the rules and regulations of the
Commission thereunder.

                                         Very truly yours,



                                         /s/ Debevoise & Plimpton