EXHIBIT 10.7

                                                               EXECUTION VERSION
                                                               -----------------

                SECOND AMENDMENT TO SECURITIES PURCHASE AGREEMENT

     This Second  Amendment  to  Securities  Purchase  Agreement  (this  "Second
Amendment")  is entered into as of the 29th day of October,  2004,  by and among
Carrizo Oil & Gas, Inc., a Texas  corporation  (the "Company") and the Investors
listed on the signature pages hereto (each an "Investor" and  collectively,  the
"Investors").

                              W I T N E S S E T H:
                              - - - - - - - - - -

     WHEREAS, the Company and the initial investors thereunder entered into that
certain Securities  Purchase Agreement dated as of December 15, 1999, as amended
by that  certain  First  Amendment  dated as of June 7,  2004 (as  amended,  the
"Securities Purchase Agreement"; unless otherwise defined herein, all terms used
herein with their initial letter  capitalized  shall have the meaning given such
terms in the Securities Purchase Agreement); and

     WHEREAS,  the Company has requested that the Investors amend the Securities
Purchase  Agreement  and  waive the right to an  additional  financial  covenant
arising  pursuant to Section 8.13(c) of the Securities  Purchase  Agreement as a
result of the  addition  of an EBITDA to  Interest  Expense  Ratio  covenant  to
Section 12.8(e) of the Senior Credit Agreement; and

     WHEREAS,  subject  to the  terms  and  conditions  set  forth  herein,  the
Investors have agreed to the Company's requests.

     NOW  THEREFORE,  for  and in  consideration  of the  mutual  covenants  and
agreements  herein  contained  and other good and  valuable  consideration,  the
receipt and  sufficiency of which are hereby  acknowledged  and  confessed,  the
Company and the Investors hereby agree as follows:

     SECTION 1.  Amendments.  In  reliance on the  representations,  warranties,
covenants and  agreements  contained in this Second  Amendment,  the  Securities
Purchase  Agreement  shall be  amended  effective  as of the date  hereof in the
manner provided in this Section 1.

     1.1 Amended  Definitions.  (a) The  definition  of  "Applicable  Prepayment
Premium" in Section 1.1 of the  Securities  Purchase  Agreement  shall be and it
hereby is amended and restated in its entirety to read as follows:

          "Applicable Prepayment Premium" means, at any date of determination in
     connection  with a prepayment of the Notes in accordance  with Sections 3.5
     and 3.6 hereof  during any period set forth  below,  an amount equal to the
     amount set forth below opposite such period:



                   Prepayment Rate During the Period                        % of Principal Being Paid
                   ---------------------------------                        -------------------------
                                                                             
                   June 1, 2004 to and including the
                   fifth anniversary of the Closing Date                                          3%

                                       1


                   At anytime after the fifth anniversary of the
                   Closing Date to and including the eighth
                   anniversary of the Closing Date                                                1%

                   At anytime after the eighth anniversary
                   of the Closing Date                                                            0%


          (b)  Subparagraph  (a) of the definition of "Senior  Indebtedness"  in
     Section1.1 of the Securities  Purchase  Agreement shall be and it hereby is
     amended in its entirety to read as follows:

          (a) all "Indebtedness" as defined in the Senior Credit Agreement,  now
     existing or hereinafter created;

     1.2  Additional  Definitions.   Section  1.1  of  the  Securities  Purchase
Agreement shall be and it hereby is amended by adding the following  definitions
in proper alphabetical order:

          "Applicable Period" as defined in Section 12.15.

          "Disclosure Notice" as defined in Section 12.15.

          "Registrable  Securities"  as defined  in the  Secured  Note  Purchase
     Agreement.

          "Secured  Note  Purchase  Agreement"  means that certain Note Purchase
     Agreement  dated as of October  29,  2004,  by and among the  Company,  the
     Secured Noteholders, and PCRL Investments L.P., as collateral agent for the
     Secured   Noteholders,   as  such  agreement  may  be  amended,   restated,
     refinanced, replaced, supplemented or modified from time to time.

          "Secured  Notes" means the 10% Senior  Subordinated  Secured Notes due
     December 15, 2008 issued by the Company to the Secured Noteholders pursuant
     to the terms of the Secured Note Purchase Agreement,  as such notes, may be
     amended, restated, supplemented or modified from time to time.

          "Secured  Noteholders"  means  the  holders  from  time to time of the
     Secured Notes issued pursuant to the Secured Note Purchase Agreement.

          "Senior Secured  Indebtedness"  means the "Indebtedness" as defined in
     the Secured Note Purchase Agreement.

          "Trading Day" as defined in the Secured Note Purchase Agreement.

     1.3 Indebtedness.

     (a)  Subparagraph (k) of Section 8.1 of the Securities  Purchase  Agreement
shall  be and it  hereby  is  amended  by  deleting  "and"  at the  end of  such
subparagraph.

                                       2


     (b)  Subparagraph (l) of Section 8.1 of the Securities  Purchase  Agreement
shall  be  and it  hereby  is  amended  by  deleting  "."  at  the  end of  such
subparagraph and inserting ";" in lieu thereof.

     (c)  Subparagraph (m) of Section 8.1 of the Securities  Purchase  Agreement
shall  be  and it  hereby  is  amended  by  deleting  "."  at  the  end of  such
subparagraph and inserting "; and" in lieu thereof.

     (d) Section 8.1 of the Securities  Purchase  Agreement is hereby amended by
adding the following subparagraph at the end of such section:

          (m) The Senior Secured Indebtedness.

     1.4 Liens.

     (a)  Subparagraph (p) of Section 8.2 of the Securities  Purchase  Agreement
shall  be and it  hereby  is  amended  by  deleting  "and"  at the  end of  such
subparagraph.

     (b)  Subparagraph (q) of Section 8.2 of the Securities  Purchase  Agreement
shall  be  and it  hereby  is  amended  by  deleting  "."  at  the  end of  such
subparagraph and inserting ";" in lieu thereof.

     (c)  Subparagraph (r) of Section 8.2 of the Securities  Purchase  Agreement
shall  be  and it  hereby  is  amended  by  deleting  "."  at  the  end of  such
subparagraph and inserting "; and" in lieu thereof.

     (d) Section 8.2 of the Securities  Purchase  Agreement is hereby amended by
adding the following subparagraph at the end of such section:

          (m) Liens securing the Senior Secured Indebtedness.

     1.5 Repurchase of Common Stock.

          Section 8.5(a) of the Securities  Purchase  Agreement  shall be and it
     hereby is amended by adding the following subsection at the end thereof:

          and (vi) the Company may repurchase  its common stock as  contemplated
     by Section 2(c) of the  Registration  Rights  Agreement  (as defined in the
     Secured Note Purchase Agreement).

     1.6  Restrictions on Ability of Subsidiaries to Make or Repay  Intercompany
Loans.

          Section  8.5(b)(ii) of the Securities  Purchase Agreement shall be and
     it hereby is  amended by adding the  following  provision  after the phrase
     "permitted Secured Indebtedness)":

          and Section 7.6 of the Secured Note Purchase Agreement

                                       3


     1.7  Confidentiality.  Section 12.15 of the Securities  Purchase  Agreement
shall be and it hereby is  amended by adding  the  following  at the end of such
section:

          (a) For the purposes of this Section 12.15, "Confidential Information"
     means information  delivered to any Investor by or on behalf of the Company
     or any Subsidiary in connection  with the  transactions  contemplated by or
     otherwise   pursuant  to  this  Agreement  and  the  other  Note  Documents
     (including,  without limitation, any information regarding the transactions
     contemplated  by the Secured  Note  Purchase  Agreement  provided  prior to
     October 29, 2004) that is identified as confidential  or should  reasonably
     be known to be  confidential,  provided  that such  term  does not  include
     information that (i) was publicly known or otherwise known to such Investor
     prior to the time of such disclosure,  (ii)  subsequently  becomes publicly
     known  through no act or omission by any  Investor or any Person  acting on
     its behalf,  or (iii)  otherwise  becomes known to any Investor  other than
     through disclosure by the Company or any Subsidiary.

          (b) Subject to Section  12.15(e),  each  Investor  will  maintain  the
     confidentiality  of  such  Confidential   Information  in  accordance  with
     procedures  adopted by such Investor in good faith to protect  confidential
     information of third parties delivered to such Investor, provided that such
     Investor may deliver or disclose Confidential  Information to the following
     Persons as to whom the Investor remains  responsible for their  maintenance
     of  confidentiality  to the extent  required herein (other than the Persons
     described in clauses (iii), (vi) and (vii)),  (i) its directors,  officers,
     employees,  agents, attorneys and affiliates (to the extent such disclosure
     reasonably relates to the  administration of the investment  represented by
     the Notes), (ii) its financial advisors and other professional advisors who
     are made aware of the confidential  nature of such  information,  (iii) any
     other holder of Notes, (iv) any eligible Person to which any Investor sells
     or offers to sell Notes or any part  thereof or any  participation  therein
     (if  such  Person  has  agreed  in  writing  prior to its  receipt  of such
     Confidential  Information  to be bound by the  provisions  of this  Section
     12.15),  (v) any Person from which such  Investor  offers to  purchase  any
     security of the Company (if such Person has agreed in writing  prior to its
     receipt of such  Confidential  Information to be bound by the provisions of
     this Section 12.15), (vi) any federal or state regulatory  authority having
     jurisdiction  over  such  Investor,   (vii)  the  National  Association  of
     Insurance  Commissioners  or any similar  organization,  or any  nationally
     recognized  rating agency that  requires  access to  information  about its
     investment portfolio,  or (viii) any other Person to which such delivery or
     disclosure may be necessary or appropriate  (w) to effect  compliance  with
     any law,  rule,  regulation or order  applicable to such  Investor,  (x) in
     response to any subpoena or other legal process, (y) in connection with any
     litigation  to which such Investor is a party or (z) if an Event of Default
     has occurred and is continuing,  to the extent such Investor may reasonably
     determine  such delivery and  disclosure to be necessary or  appropriate in
     the  enforcement or for the protection of the rights and remedies under the
     Notes and this Agreement.

          (c) Each Investor,  by its acceptance of Notes, will be deemed to have
     agreed to be bound by and to be  entitled to the  benefits of this  Section
     12.15 as though it were a party to this Agreement. On reasonable request by
     the Company in connection  with the delivery to any Investor of information
     required to be delivered to such Investor under


                                       4


     this  Agreement or requested by such Investor  (other than an Investor that
     is a party to this  Agreement or its nominee) such Investor will enter into
     an agreement  with the Company  embodying  the  provisions  of this Section
     12.15.

          (d)  Notwithstanding  anything to the contrary  herein or in any other
     Note  Document  and unless  otherwise  requested  by  written  notice of an
     Investor to the Company,  the Company  shall have no  obligation to deliver
     any Confidential Information to any Investor.

          (e) If at any time after the Closing Date:

               (i) any  Confidential  Information not disclosed to such Investor
          prior to October 29, 2004 that is material  and  non-public  regarding
          the Company or any of its  Subsidiaries is delivered to an Investor by
          or on behalf of the Company or any  Subsidiary in connection  with the
          transactions  contemplated by or otherwise  pursuant to this Agreement
          prior to delivery of the written notice specified in Section 12.15(d);

               (ii)  at  such  time  (A)  such   Investor,   together  with  its
          Affiliates, is the holder of Registrable Securities (as defined in the
          Secured Note Purchase  Agreement)  representing five one-hundredths of
          one percent  (0.05%) or more of the  outstanding  Common  Stock of the
          Company;  or (B) the  Issue  Date  related  to any  Significant  Stock
          Payment  Notice (as defined in the Secured  Note  Purchase  Agreement)
          issued to such Investor or any of its Affiliates has not occurred; and

               (iii)  such  Investor  delivers  written  notice  to the  Company
          indicating  that  an  Applicable   Period  has  begun  (a  "Disclosure
          Notice"),

               then as of the end of the  Applicable  Period  set  forth in such
          Disclosure  Notice (or such  earlier  date as the  Company  shall have
          complied with clause (x) of this Section  12.15(e)(iii))  (unless such
          Confidential  Information  is no  longer  material,  or  is no  longer
          Confidential Information):

                    (x)  the  Company   shall  be  obligated  to  disclose  such
               Confidential Information in a manner compliant with Regulation FD
               of the  Exchange  Act and in  sufficient  detail  such  that such
               Investor  shall not be restricted  from trading the securities of
               the Company  under the U.S. or any state  securities  laws due to
               its knowledge of such Confidential Information;

                    (y) the  obligations to keep such  Confidential  Information
               confidential   and  not  trade  while  in   possession   of  such
               information  of  such  Investor  under  Section   12.15(b)  shall
               terminate; and

                    (z) to the extent the Company  shall not have  complied with
               clause (x) of this Section  12.15(e)(iii) prior to the end of the
               Applicable  Period,  such Investor,  without  liability,  risk or
               obligation  to  the  Company  or any  of  its  Subsidiaries,  may
               (following consultation with the Company, to the extent possible)
               disclose such Confidential Information in a manner


                                       5


               compliant with Regulation FD of the Exchange Act but only in such
               detail  such that such  Investor  shall  not be  restricted  from
               trading the securities of the Company under the U.S. or any state
               securities  laws  due  to  its  knowledge  of  such  Confidential
               Information.

                    (f) For purposes of this Section 12.15,  "Applicable Period"
               means,  as  of  the  date  any  Investors  receives  Confidential
               Information  prior to delivery of the written notice specified in
               Section 12.15(d) with respect to such  Confidential  Information,
               the period  specified in the table below  opposite the percentage
               ownership  of the  outstanding  shares  of  Common  Stock  of the
               Company  represented  by  the  aggregate  number  of  Registrable
               Securities  issued to such Investor and its Affiliates during the
               period  of  thirty  (30)  consecutive  Trading  Days  immediately
               preceding  but excluding  such date plus the aggregate  number of
               shares of  Registrable  Securities  to be issued  pursuant to any
               Significant Stock Payment Notice then in effect:



                      ------------------------------------- ----------------------------------
                              Percentage Ownership                   Applicable Period
                      ------------------------------------- ----------------------------------
                                                                 
                        More than 0.05% but less than or        Twelve (12) Trading Days
                                 equal to .75%
                      ------------------------------------- ----------------------------------
                        More than .75% but less than or           Five (5) Trading Days
                                 equal to 1.5%
                      ------------------------------------- ----------------------------------
                                 More than 1.5%                  Three (3) Trading Days
                      ------------------------------------- ----------------------------------


                    The Trading Days  included in any  Applicable  Period during
               which  any  Investor  is  not   permitted  to  sell   Registrable
               Securities  shall be included in the  determination of whether an
               "Event" has occurred as such term is defined in and to the extent
               provided by the Registration  Rights Agreement (as defined in the
               Secured Notes Purchase  Agreement) and to the extent such Trading
               Days include Trading Days that would otherwise be included in any
               Measurement  Period (as  defined in the  Secured  Notes  Purchase
               Agreement),   such  Trading  Days  shall  be  excluded  for  such
               Measurement  Period as if such Trading Days were not Trading Days
               (it  being  understood  that  such  Measurement  Period  shall be
               extended so that the  Measurement  Period is the full  applicable
               period of Trading Days), and the date for any payment relating to
               such Measurement  Period shall be extended for the number of days
               equal to the Trading Days excluded from the Measurement Period.

     SECTION 2. Waiver.  Effective as of the date hereof,  upon  satisfaction of
the conditions  precedent set forth in Section 4.4 hereof,  and in reliance upon
the  representations  and  warranties of the Company set forth in the Securities
Purchase Agreement and in this Second Amendment, and notwithstanding anything to
the contrary contained in the Securities Purchase Agreement  (including pursuant
to Section 8.13(c) of the Securities Purchase  Agreement),  the Investors hereby
waive their right to an additional financial covenant to the Securities Purchase
Agreement  arising pursuant to Section 8.13(c) as a result of the addition of an
EBITDA to  Interest  Expense  Ratio to  Section  12.8(e)  of the  Senior  Credit
Agreement.  Nothing  contained  herein shall  obligate any Investor to grant any
additional or future waiver of the obligations to comply with Section


                                       6


8.13(c) of the Securities  Purchase  Agreement or any other provision thereof or
any other Note Document.

     SECTION 3. Representations and Warranties. In order to induce the Investors
to enter into this Second Amendment,  the Company hereby represents and warrants
to the Investors that upon the effectiveness of this Second Amendment:

          (a) each  representation  and warranty of the Company contained in the
     Securities  Purchase Agreement is true and correct in all material respects
     as of the date hereof  (except to the extent  that any such  representation
     and warranty is expressly made as of a particular date, in which event such
     representation and warranty was true and correct as of such date);

          (b) neither a Default nor an Event of Default  has  occurred  which is
     continuing; and

          (c) the Company does not have any  defenses to payment,  counterclaims
     or rights of set-off with respect to any of its obligations pursuant to the
     Securities Purchase Agreement on the date hereof.

     SECTION 4. Miscellaneous.

     4.1  Reaffirmation.  The terms  and  provisions  set  forth in this  Second
Amendment  shall modify and supersede all  inconsistent  terms and provisions of
the Securities Purchase Agreement and shall not be deemed to be a consent to the
modification or waiver of any other term or condition of the Securities Purchase
Agreement. Except as expressly modified and superseded by this Second Amendment,
the terms and provisions of the Securities  Purchase  Agreement are ratified and
confirmed and shall continue in full force and effect.

     4.2 Parties in  Interest.  All of the terms and  provisions  of this Second
Amendment  shall bind and inure to the benefit of the  parties  hereto and their
respective successors and assigns.

     4.3 Expenses.  The Company  hereby  agrees to pay on demand all  reasonable
fees and  expenses  of counsel to the  Investors  incurred by the  Investors  in
connection  with the  preparation,  negotiation  and  execution  of this  Second
Amendment and all related documents.

     4.4  Effectiveness.  This Second  Amendment  shall  become  effective  upon
satisfaction of each of the conditions precedent set forth in this Section 4.4.

          A. The Company and the  Investors  shall have  executed and  delivered
this Second Amendment.

          B. No Default or Event of Default shall exist.

          C.  The  Investors  shall  have  received  a copy  of a duly  executed
amendment to the Senior Credit Agreement in form and substance acceptable to the
Investors.

                                       7


     4.5  Counterparts.  This Second  Amendment may be executed in counterparts,
and all parties need not execute the same counterpart;  however,  no party shall
be bound by this Second  Amendment until this Second Amendment has been executed
by the Company and the  Investors at which time this Second  Amendment  shall be
binding on, enforceable  against and inure to the benefit of the Company and the
Investors. Facsimiles shall be effective as originals.

     4.6 COMPLETE AGREEMENT.  THE SECURITIES PURCHASE AGREEMENT, AS AMENDED, AND
THE OTHER DOCUMENTS  REPRESENT THE FINAL AGREEMENT AMONG THE PARTIES AND MAY NOT
BE CONTRADICTED BY EVIDENCE OF PRIOR,  CONTEMPORANEOUS OR ORAL AGREEMENTS OF THE
PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

     4.7 Headings.  The headings,  captions and arrangements used in this Second
Amendment are, unless specified otherwise, for convenience only and shall not be
deemed to limit,  amplify  or modify  the terms of this  Second  Amendment,  nor
affect the meaning thereof.

     4.8  Governing  Law. THIS  AGREEMENT  SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE DOMESTIC LAWS OF THE STATE OF NEW YORK WITHOUT GIVING EFFECT
TO ANY CHOICE OR CONFLICT OF LAW  PROVISION OR RULE (WHETHER IN THE STATE OF NEW
YORK OR ANY OTHER  JURISDICTION) THAT WOULD CAUSE THE APPLICATION OF THE LAWS OF
ANY JURISDICTION OTHER THAN THE STATE OF NEW YORK.


                            [Signature pages follow]




                                       8


     IN WITNESS  WHEREOF,  this Second  Amendment  has been duly executed by the
parties set forth below as of the date first written above.

CARRIZO OIL & GAS, INC.


By: /s/ PAUL F. BOLING
    -------------------------------------------------
Name: Paul F. Boling
Title:   Vice President and Chief Financial Officer








INVESTORS:

STEELHEAD INVESTMENTS LTD.

By:      HBK Investments L.P.
Title:   Investment Advisor


         By: /s/ WILLIAM E. ROSE
             -------------------------------------------------
         Name: William E. Rose
         Title:   Authorized Signatory