**STOCK
      OPTION AGREEMENT**




THIS
      STOCK OPTION AGREEMENT (“Agreement”) is made by and between LIXTE BIOTECHNOLOGY
      HOLDINGS, INC, a Delaware corporation (the “Company”), and FRANCIS
      JOHNSON (the
“Optionee”).




WHEREAS,
      Concurrently herewith, Optionee has entered into a Consulting Agreement with
      the
      Company (the “Consulting Agreement”).




NOW,
      THEREFORE, in consideration of the mutual benefit to be derived herefrom and
      pursuant to the Consulting Agreement, the Company and Optionee agree as
      follows:




1.  Grant
      of Option .
      The
      Company hereby grants to Optionee the right, privilege and option (“Option”) to
      purchase 300,000 shares of its common stock (“Stock”) at an exercise price of
      $0.33 1/3 per share, in the manner and subject to the conditions provided
      hereinafter.




2.  Vesting
      and Exercise of Option .
      The
      Optionee shall be vested in 1/3 of the total number of shares subject to the
      Option on the first anniversary of this Agreement; 1/3 of the total shares
      subject to the Option shall vest on the second anniversary on the date of this
      Agreement and 1/3 of the total shares subject to the Option shall vest on the
      third anniversary of the date of this Agreement. Any exercise may be with
      respect to any part or all of the shares then vested and exercisable pursuant
      to
      such Option.




3.  Termination
      of Option .
      Except
      as otherwise provided in this Agreement, to the extent not previously exercised,
      the Option shall terminate upon the first to occur of any of the following
      events:




a.  Four
      years from the date of the vesting of a particular tranche
      hereunder;




b.  the
      date
      the Consulting Agreement is terminated; or




c.  the
      breach by Optionee of any provision of this Agreement.




4.  Method
      of Exercise .
      An
      Option shall be exercised by written notice to the Company by the Optionee
      (or
      successor in the event of death). Such written notice shall state the number
      of
      shares with respect to which the Option is being exercised and designate a
      time,
      during normal business hours of the Company, for the delivery thereof ("Exercise
      Date"), which time shall be at least ten days after the giving of such notice
      unless an earlier date shall have been mutually agreed upon. At the time
      specified in the written notice, the Company shall deliver to the Optionee
      at
      the principal office of the Company, or such other appropriate place as may
      be
      determined by the Board, a certificate or certificates for such shares.
      Notwithstanding the foregoing, the Company may postpone delivery of any
      certificate or certificates after notice of exercise for such reasonable period
      as may be required to comply with any applicable listing requirements of any
      securities exchange. In the event an Option shall be exercisable by any person
      other than the Optionee, the required notice under this Section shall be
      accompanied by appropriate proof of the right of such person to exercise the
      option. The option exercise price shall be payable in full on or before the
      option Exercise Date by full payment in cash or certified bank or cashier's
      check.







5.  Restrictions
      on Exercise and Delivery .
      The
      exercise of each Option shall be subject to the condition that, if at any time
      the Board shall determine, in its sole and absolute discretion,




a.  the
      satisfaction of any withholding tax or other withholding liabilities, is
      necessary or desirable as a condition of, or in connection with, such exercise
      or the delivery or purchase of Stock pursuant thereto,




b.  the
      listing, registration, or qualification of any shares deliverable upon such
      exercise is desirable or necessary, under any state or federal law, as a
      condition of, or in connection with, such exercise or the delivery or purchase
      of shares pursuant thereto, or




c.  the
      consent or approval of any regulatory body is necessary or desirable as a
      condition of, or in connection with, such exercise or the delivery or purchase
      of shares pursuant thereto,




then
      in
      any such event, such exercise shall not be effective unless such withholding,
      listing, registration, qualification, consent or approval shall have been
      effected or obtained free of any conditions not acceptable to the Board.
      Optionee shall execute such documents and take such other actions as are
      required by the Board to enable it to effect or obtain such withholding,
      listing, registration, qualification, consent or approval. Neither the Company
      nor any officer or member of the Board or the Committee, shall have any
      liability with respect to the non-issuance or failure to sell shares as the
      result of any suspensions of exercisability imposed pursuant to this
      Section.




6.  Nonassignability .
      Options
      may not be sold, pledged, assigned or transferred in any manner other than
      by
      will or by the laws of intestate succession, and may be exercised during the
      lifetime of Optionee only by Optionee. Any transfer by Optionee of any Option
      granted under this Agreement shall void such Option and the Company shall have
      no further obligation with respect to such Option. No Option shall be pledged
      or
      hypothecated in any way, nor shall any Option be subject to execution,
      attachment or similar process.




7.  Restrictive
      Legends .
      Each
      certificate evidencing the shares acquired upon exercise of an Option hereunder,
      including any certificate issued to any transferee thereof, shall be imprinted
      with appropriate legends.




8.  Rights
      as Shareholder .
      Neither
      Optionee nor his executor, administrator, heirs or legatees, shall be, or have
      any rights or privileges of a shareholder of the Company in respect of the
      Stock
      unless and until certificates representing such Stock shall have been issued
      in
      Optionee’s name.




9.  Notices .
      Any
      notice to be given under the terms of this Agreement shall be addressed to
      the
      Company in care of its Secretary at its principal office, and any notice to
      be
      given to Optionee shall be addressed to such Optionee at the address maintained
      by the Company for such person or at such other address as the Optionee may
      specify in writing to the Company.




10.  Binding
      Effect .
      This
      Agreement shall be binding upon and inure to the benefit of Optionee, his heirs
      and successors, and of the Company, its successors and assigns.




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11.  Governing
      Law .
      This
      Agreement shall be governed by the laws of the State of Delaware.




IN
      WITNESS WHEREOF, this Agreement is effective as of, and the date of grant shall
      be September 12, 2007.




**LIXTE
                BIOTECHNOLOGY HOLDINGS, INC**By:_________________________________
              Name:John
                S. Kovach
              Title:President**OPTIONEE**____________________________________Francis
                Johnson







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