EXHIBIT 5.1

                                October 3, 2005

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

Gentlemen:

      We have acted as counsel to Northfield Laboratories Inc., a Delaware
corporation (the "Company"), in connection with the Registration Statement on
Form S-8 (the "Registration Statement") filed by the Company under the
Securities Act of 1933, as amended, with the Securities and Exchange Commission
(the "Commission"), relating to the sale of up to 1,500,000 shares (the
"Shares") of the Company's Common Stock, par value $.01 per share, pursuant to
the Northfield Laboratories Inc. 2003 Equity Compensation Plan, as amended and
restated (the "Plan"). We have examined the Registration Statement as filed by
the Company with the Commission. We have additionally reviewed such other
documents and have made such further investigations as we have deemed necessary
to enable us to express the opinion hereinafter set forth.

      Based on the foregoing, we hereby advise you that in our opinion the
Shares have been duly authorized by the Company and will, when issued in
accordance with the terms and conditions of the Plan, be validly issued, fully
paid and nonassessable.

      We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. 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 of 1933, as amended, or the rules and regulations
thereunder.

                                Very truly yours,


                                /s/ Baker & McKenzie LLP
                                BAKER & MCKENZIE LLP