U.S. SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549

FORM 12b-25

NOTIFICATION OF LATE FILING

SEC FILE NO. 1-32639

CUSIP NUMBER 563118207

(Check One):

o Form 10-K  o Form 20-F  oForm 11-K  x Form 10-Q
o Form N-SAR  oForm N-CSR


For Period Ended: March 31, 2010

 o Transition Report on Form 10-K
 o Transition Report on Form 20-F
 o Transition Report on Form 11-K
 o Transition Report on Form 10-Q
 o Transition Report on Form N-SAR
For the Transition Period Ended: ____________________


Read Instruction (on back page) Before Preparing Form.  Please Print or Type.

Nothing in this form shall be construed to imply that the Commission has verified any information contained herein.

 
If the notification relates to a portion of the filing checked above, identify the Item(s) to which the notification relates:


 
Part I -- Registrant Information

Full Name of Registrant: Manhattan Pharmaceuticals, Inc.

Former Name if Applicable: N/A

Address of Principal Executive Office: 48 Wall Street, New York, New York 10005


Part II -- Rules 12b-25(b) and (c)

If the subject report could not be filed without unreasonable effort or expense and the registrant seeks relief pursuant to Rule 12b-25(b), the following should be completed.  (Check box if appropriate)

 
(a)
The reasons described in reasonable detail in Part III of this form could not be eliminated without unreasonable effort or expense;
     
þ
(b)
The subject annual report, semi-annual report, transition report on Form10-K, Form 20-F, Form 11-K, Form N-SAR, or Form N-CSR, or portion thereof, will be filed on or before the fifteenth calendar day following the prescribed due date; or the subject quarterly report or transition report on Form 10-Q or subsequent distribution report on Form 10-D, or portion thereof, will be filed on or before the fifth calendar day following the prescribed due date; and
 
 
(c)
The accountant's statement or other exhibit required by Rule 12b-25(c) has been attached if applicable.


  Part III -- Narrative

State below in reasonable detail the reasons why Forms 10-K, 20-F, 11-K, 10-Q, 10-D, N-SAR, N-CSR, or the transition report or portion thereof, could not be filed within the prescribed time period.

Manhattan Pharmaceuticals, Inc. (the "Registrant") is unable to file its quarterly report on Form 10-Q for the three month period ended March 31, 2010, within the time period prescribed for such report without unreasonable effort or expense.  Completion of the Registrant's recent merger with Ariston Pharmaceuticals, Inc. delayed the Registrant’s completion of its financial statements and, as a result, its quarterly report on Form 10-Q cannot be filed within the prescribed time period.

Part IV -- Other Information

(1)  Name and telephone number of person to contact in regard to this notification.

Michael McGuinness
Chief Financial and Operating Officer
212-582-3950
(Name and Title)     (Area Code) (Telephone Number)
   
                                                                             


(2)  Have all other periodic reports required under Sections 13 or 15(d) of the Securities Exchange Act of 1934 or Section 30 of the Investment Company Act of 1940 during the preceding 12 months or for such shorter period that the registrant was required to file such report(s) been filed?  If answer is no, identify report(s).
þ Yes                        o No

(3)  Is it anticipated that any significant change in results of operations from the corresponding period for the last fiscal year will be reflected by the earnings statements to be included in the subject report or portion thereof?
¨Yes        þ No

If so, attach an explanation of the anticipated change, both narratively and quantitatively, and, if appropriate, state the reasons why a reasonable estimate of the results cannot be made.


Manhattan Pharmaceuticals, Inc.

(Name of Registrant as Specified in Charter)

has caused this notification to be signed on its behalf by the undersigned hereunto duly authorized.

Date: May 17, 2010
By: /s/ Michael McGuiness
Name: Michael McGuinness
Title: Chief Financial and Operating Officer
 
INSTRUCTION:  The form may be signed by an executive officer of the registrant or by any other duly authorized representative.  The name and title of the person signing the form shall be typed or printed beneath the signature.  If the statement is signed on behalf of the registrant by an authorized representative (other than an executive officer), evidence of the representative's authority to sign on behalf of the registrant shall be filed with the form.
 
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Intentional misstatements or omissions of fact constitute Federal Criminal Violations (See 18 U.S.C. 1001)