Exhibit 5

February 23, 2001

Board of Directors
Guilford Pharmaceuticals Inc.
6611 Tributary Street
Baltimore, Maryland 21224

Ladies and Gentlemen:

      We are acting as counsel to Guilford Pharmaceuticals Inc., a Delaware corporation (the “Company”), in connection with its registration statement on Form S-8, as amended (the “Registration Statement”), filed with the Securities and Exchange Commission relating to the registration of up to 1,710,175 shares (the “Shares”) of the Company’s common stock, par value $ .01 per share, issuable in connection with the Guilford Pharmaceuticals Inc. 1993 Employee Share Option and Restricted Share Plan (the “Plan”) and the Share Option Agreement (Susan Smith) (the “Share Option Agreement”). This opinion letter is furnished to you at your request to enable you to fulfill the requirements of Item 601(b)(5) of Regulation S-K, 17 C.F.R. § 229.601(b)(5), in connection with the Registration Statement.

      For purposes of this opinion letter, we have examined copies of the following documents:

1.	An executed copy of the Registration Statement.
2.	A copy of the Plan.
3.	A copy of the Share Option Agreement.
4.	The Certificate of Incorporation of the Company with amendments thereto, as certified by the Secretary of the State of the State of Delaware on February 16, 2001 and by the Secretary of the Company on the date hereof as being complete, accurate, and in effect.

5.	The Bylaws of the Company, as certified by the Secretary of the Company on the date hereof as being complete, accurate, and in effect.
6.	Resolutions of the Board of Directors of the Company adopted as of February 19, 2001, November 14, 2000, and February 18, 1997 and a report on the vote of the Stockholders on May 21, 1997 as certified by the Secretary of the Company on the date hereof as being complete, accurate, and in effect, relating to, among other things, the amendment of the Plan, approval of the Share Option Agreement and the filing of the Registration Statement.
7.	A certificate of an officer of the Company, dated the date hereof, as to certain facts relating to the Company.

      In our examination of the aforesaid documents, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the accuracy and completeness of all documents submitted to us, the authenticity of all original documents, and the conformity to authentic original documents of all documents submitted to us as copies (including telecopies). This opinion letter is given, and all statements herein are made, in the context of the foregoing.

      This opinion letter is based as to matters of law solely on the Delaware General Corporation Law, as amended. We express no opinion herein as to any other laws, statutes, ordinances, rules, or regulations. As used herein, the term “Delaware General Corporation Law, as amended” includes the statutory provisions contained therein, all applicable provisions of the Delaware Constitution and reported judicial decisions interpreting these laws.

      Based upon, subject to and limited by the foregoing, we are of the opinion that following (i) effectiveness of the Registration Statement, (ii) issuance of the Shares pursuant to the terms of the Plan, the Share Option Agreement and in the manner contemplated by the Registration Statement and (iii) receipt by the Company of the consideration (the form of which is accordance with applicable law) for the Shares, the Shares will be validly issued, fully paid and nonassessable.

      This opinion letter has been prepared for your use in connection with the Registration Statement and speaks as of the date hereof. We assume no obligation to advise you of any changes in the foregoing subsequent to the delivery of this opinion letter.

      We hereby consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement and to the reference to this firm under the caption “Legal Matters” in the prospectus constituting a part of the Registration Statement. In giving this consent, we do not thereby admit that we are an “expert” within the meaning of the Securities Act of 1933, as amended.

Very truly yours,

/s/ Hogan & Hartson L.L.P.

HOGAN & HARTSON L.L.P.