Exhibit 5.1

Maslon Edelman Borman & Brand, LLP

90 South Seventh Street, Suite 3300

Minneapolis, Minnesota 55402

(612) 672-8200

June 18, 2007

Manhattan Pharmaceuticals, Inc.

810 Seventh Avenue, 4th Floor

New York, New York 10019

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have acted on behalf of Manhattan Pharmaceuticals, Inc.(the “Company”) in connection with a Registration Statement on Form S-8 (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission relating to the registration of an aggregate of 5,000,000 shares of common stock (the “Shares”), issued or to be issued by the Company, pursuant to the terms of the Company's 2003 Stock Option Plan (the “Plan”). Upon examination of such corporate documents and records as we have deemed necessary or advisable for the purposes hereof, it is our opinion that the Shares, when issued and paid for as contemplated by the Plan, and when delivered against payment thereof in the manner contemplated by the Plan, will be validly issued, fully paid and non-assessable.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement.

Very truly yours,

/s/ Maslon Edelman Borman & Brand, LLP