EXHIBIT 5.1

                         [BAKER & MCKENZIE LETTERHEAD]

May 14, 2004

Northfield Laboratories Inc.
1560 Sherman Avenue
Suite 1000
Evanston, IL  60201-4800

Re: Offering of Common Stock

Ladies and Gentlemen,

We have acted as counsel for Northfield Laboratories Inc., a Delaware
corporation (the "Company"), in connection with the registration under the
Securities Act of 1933, as amended (the "Securities Act"), of the offer and sale
of up to 1,954,416 shares of the Company's Common Stock, par value $.01 per
share (the "Stock"), pursuant to the Registration Statement on Form S-3
(Registration Number 333-106615) filed by the Company with the Securities and
Exchange Commission (the "Commission") on June 27, 2003 (the "June 2003
Registration Statement") and the Registration Statement on Form S-3
(Registration Number 333-115459) filed by the Company with the Commission on May
13, 2004 pursuant to Rule 462(b) under the Securities Act (together with the
June 2003 Registration Statement, collectively the "Registration Statement").

The offering and sale of the Stock is proposed to be made pursuant to that
certain Placement Agent Agreement dated as of May 12, 2004 (the "Placement Agent
Agreement") executed by the Company and SG Cowen & Co., LLC (the "Placement
Agent"). Unless otherwise defined herein, each capitalized term used herein that
is defined in the Placement Agent Agreement has the meaning given such term in
the Placement Agent Agreement.

In reaching the opinion set forth herein, we have reviewed copies of the
Placement Agent Agreement, the Placement Agent's Warrant issued by the Company
to the Placement Agent pursuant to the Placement Agent Agreement (the "Placement
Agent's Warrant"), and the Subscription Agreements executed by the Company and
each of the purchasers (the "Purchasers") of the Stock (the "Subscription
Agreements"), the Registration Statement, the Prospectus included in the June
2003 Registration Statement as of its effective date (the "Base Prospectus"),
the Prospectus Supplement filed by the Company with the Commission on May 13,
2004 (the "Prospectus Supplement") and such other agreements, certificates of
public officials and officers of the Company, records, documents and matters of
law that we have deemed relevant. The Placement Agent Agreement, the Placement
Agent's Warrant and the Subscription Agreements are referred to herein
collectively as the "Transaction Documents."

We have reviewed executed copies of the Transaction Documents and we have
examined the originals, or photostatic or certified copies, of such records of
the Company, of certificates of officers of the Company and of public documents,
and such other documents as we have deemed relevant and necessary as the basis
of the opinions set forth below. In such examination, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents of all documents submitted to
us as photostatic or certified copies and the authenticity of the originals of
such copies.



Based upon and subject to the foregoing, we are of the opinion that the Stock
has been duly and validly authorized and, when issued to the Purchasers in
accordance with the terms of the Subscription Agreements, will be validly
issued, fully paid and nonassessable.

The opinion expressed above is limited to the laws of the General Corporation
Law of the State of Delaware and the federal laws of the United States of
America.

This opinion letter is limited to the matters stated herein and no opinion is
implied or may be inferred beyond the matters expressly stated.

We hereby consent to the use of our opinion as herein set forth as an exhibit to
the Registration Statement and to the use of our name under the caption "Legal
Matters" in the Base Prospectus and the Prospectus Supplement. In giving this
consent, we do not hereby admit that we come within the category of persons
whose consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission promulgated thereunder or Item 509 of Regulation
S-K.

Very truly yours,

/S/  BAKER & MCKENZIE

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