Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
WEISER MICHAEL
   2. Issuer Name and Ticker or Trading Symbol
ZIOPHARM ONCOLOGY INC [ZIOP] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O ZIOPHARM ONCOLOGY, INC., 1180 AVENUE OF THE AMERICAS, SUITE 1920		 3. Date of Earliest Transaction (Month/Day/Year)
05/25/2011
(Street)

NEW YORK, NY 10036		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock, $.001 par value 05/25/2011   S(1)   15,000 D $ 6.53 (1) 135,945 (2) D  

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Warrants to Purchase Common Stock $ 4.75             09/13/2005 05/31/2012 Common Stock, $.001 par value 35,566   35,566 D  
Director Stock Option (right to buy) $ 4.31             07/20/2007 12/22/2014 Common Stock, $.001 par value 15,029   15,029 D  
Director Stock Option (right to buy) $ 5.01             04/26/2006 04/26/2016 Common Stock, $.001 par value 15,000   15,000 D  
Warrants to purchase Common Stock $ 5.09             05/03/2006 05/03/2013 Common Stock, $.001 par value 18,319   18,319 D  
Director Stock Option (right to buy) $ 6.49             12/13/2009 12/13/2016 Common Stock, $.001 par value 15,000   15,000 D  
Stock Option (right to buy) $ 4.85             06/18/2010 06/18/2017 Common Stock 15,000   15,000 D  
Stock Option (right to buy) $ 2.73               (3) 12/12/2017 Common Stock 20,000   20,000 D  
Stock Option (right to buy) $ 0.7               (4) 05/13/2019 Common Stock 15,000   15,000 D  
Stock Options (right to buy) $ 2.85               (5) 12/31/2019 Common Stock, $.001 par value 7,500   7,500 D  
Stock Options (right to buy) $ 5.09             03/31/2011 03/31/2020 Common Stock, $.001 par value 15,000   15,000 D  
Stock Option (right to buy) $ 4.77               (6) 12/31/2020 Common Stock 30,000   30,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
WEISER MICHAEL
C/O ZIOPHARM ONCOLOGY, INC.
1180 AVENUE OF THE AMERICAS, SUITE 1920
NEW YORK, NY 10036		   X      

Signatures

 /s/ Richard E. Bagley as attorney-in-fact for Michael Weiser   05/26/2011
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Proceeds from the sales reported on this form were used to offset the reporting person's payment of tax obligations triggered by the vesting of previously awarded restricted stock. The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.51 to $6.57, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth.
(2) Includes grants of restricted stock with restrictions that lapsed as to 3,750 shares on December 31, 2010 and as to 15,000 shares on March 31, 2011; and restrictions that will lapse as to 3,750 shares on December 31, 2011.
(3) 6,667 shares vest on each of 12/12/08 and 12/12/09; 6,666 shares vest on 12/12/10.
(4) 5,000 shares vest on each of 12/31/09, 6/30/2010 and 12/31/2010.
(5) 3,750 shares vest on each of 12/31/2010 and 12/31/2011.
(6) 10,000 shares vest on each of 12/31/2011, 12/31/2012 and 12/31/2013.
 
Remarks:
Exhibit 24.1 Power of Attorney attached.

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