UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13G


                    UNDER THE SECURITIES EXCHANGE ACT OF 1934


                             ZIOPHARM ONCOLOGY, INC.


                    Common Stock, par value $0.001 per share
                         (Title of Class of Securities)

                                    98973P101
                                  CUSIP Number

                                December 31, 2005
                      (Date of Event which Requires Filing
                               of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

                                |_| Rule 13d-1(b)
                                |X| Rule 13d-1(c)
                                |_| Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

                          Continued on following pages
                                Page 1 of 5 Pages





                                  SCHEDULE 13G

CUSIP No. 563118207
                                                                     Page 2 of 5


1        Names of Reporting Persons
         I.R.S. Identification Nos. of above persons (entities only)

                  LINDSAY A. ROSENWALD, M.D.

2        Check the Appropriate Box If a Member of a Group *

                                                     a.     |_|
                                                     b.     |_|

3        SEC Use Only

4        Citizenship or Place of Organization

                  UNITED STATES

                            5             Sole Voting Power
Number of                                 760,310
  Shares
Beneficially                6             Shared Voting Power
  Owned By                                563,296
    Each
Reporting                   7             Sole Dispositive Power
    Person                                760,310
    With
                            8             Shared Dispositive Power
                                          563,296

9        Aggregate Amount Beneficially Owned by Each Reporting Person

                                    1,323,606

10       Check Box If the Aggregate Amount in Row (9) Excludes Certain
         Shares *

                                       |_|

11       Percent of Class Represented By Amount in Row (9)

                                      17.5%

12       Type of Reporting Person *

                                       IN

* see instructions before filling out




                                                                     PAGE 3 OF 5

ITEM 1(A)         NAME OF ISSUER:

                  ZioPharm Oncology, Inc. (the "Issuer")

ITEM 1(B)         ADDRESS OF THE ISSUER'S PRINCIPAL EXECUTIVE OFFICES:

                       1180 Avenue of the America's
                       New York, NY  10019

ITEM 2(A)         NAME OF PERSON FILING:

                  Lindsay A. Rosenwald, M.D. (the "Reporting Person").

ITEM 2(B)         ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE:

                       c/o Paramount BioCapital Investments, LLC
                       787 Seventh Avenue, 48th Floor
                       New York, NY 10036


ITEM 2(C)         CITIZENSHIP:
                  The Reporting Person is a citizen of the United States.

ITEM 2(D)         TITLE OF CLASS OF SECURITIES:

                  Common Stock (the "Shares").

ITEM 2(E)         CUSIP NUMBER:

                        98973P101

ITEM 3.           IF THIS  STATEMENT IS FILED  PURSUANT TO RULE  13D-1(B),
                  OR 13D-2(B) OR (C),  CHECK  WHETHER THE PERSON FILING IS A:

                  This Item 3 is not applicable.

ITEM 4.           OWNERSHIP:

ITEM 4(A)         AMOUNT BENEFICIALLY OWNED:

                        The Reporting Person beneficially owned 1,498,087
                        Shares, consisting of (i) 476,678 Shares held directly
                        by the Reporting Person; (ii) warrants to purchase
                        221,011 Shares held directly by the Reporting Person;
                        (iii) warrants to purchase 62,621 Shares held by
                        Paramount Biocapital Investments, LLC, of which the
                        Reporting Person is managing member; and (iv) 563,296
                        Shares held by certain individuals and with respect to
                        which Dr. Rosenwald has certain call rights pursuant to
                        pledge agreements to secure certain obligations. Dr.
                        Rosenwald disclaims beneficial ownership of these
                        563,296 pledged Shares, except to the extent of his
                        pecuniary interest therein, if any.




                                                                     PAGE 4 OF 5

ITEM 4(B)         PERCENT OF CLASS:

                  See Item 11 of the cover page.



ITEM 4(C)         NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:


                                                                          
         (i)      Sole power to vote or direct the vote:                       Please see Item 5 of the cover
                                                                               page.
         (ii)     Shared power to vote or to direct the vote                   Please see Item 6 of the cover
                                                                               page.
         (iii)    Sole power to dispose or to direct the disposition of        Please see Item 7 of the cover
                                                                               page.
         (iv)     Shared power to dispose or to direct the disposition of      Please see Item 8 of the cover
                                                                               page.


ITEM 5.           OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS:

                  This Item 5 is not applicable.

ITEM 6.           OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER
                  PERSON:

                  See Item 4 Above.

ITEM 7.           IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
                  ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING
                  COMPANY:

                  This Item 7 is not applicable.

ITEM 8.           IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP:

                  This Item 8 is not applicable.

ITEM 9.           NOTICE OF DISSOLUTION OF GROUP:

                  This Item 9 is not applicable.

ITEM 10. CERTIFICATION:

                  By signing below I certify that, to the best of my knowledge
and belief, the securities referred to above were not acquired and are not held
for the purpose of or with the effect of changing or influencing the control of
the issuer of the securities and were not acquired and are not held in
connection with or as a participant in any transaction having such purpose or
effect.




                                                                     PAGE 5 OF 5

                                   SIGNATURES




                  After reasonable inquiry and to the best of my knowledge and
belief, the undersigned certifies that the information set forth in this
statement is true, complete and correct.

                                                 February 10, 2006


                                                 --------------------------
                                                 Lindsay A. Rosenwald, M.D.