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                                                                    EXHIBIT 10.1


                     FIRST AMENDMENT TO EMPLOYMENT AGREEMENT

                  This AMENDMENT (the "Amendment") by and between Carrizo Oil &
Gas, Inc., a Texas corporation (the "Company"), and S. P. Johnson, IV (the
"Executive"), dated as of the ___ day of _______________, 2000 and to be
effective as of the date hereof, is an amendment to that certain Employment
Agreement by and between the Company and the Executive dated as of
______________, 1997 (the "Employment Agreement").

                                    RECITALS

                  The Company and the Executive have previously entered into the
Employment Agreement to provide for terms and conditions of the Executive's
employment by the Company; and

                  The Company and the Executive, in connection with a number of
employment related matters, have determined that is appropriate to amend the
Employment Agreement.

                  NOW, THEREFORE, IT IS HEREBY AGREED AS FOLLOWS:

         1. The parties agree that the actions of the Company's Board of
Directors, pursuant to which certain directors have or may become more active in
the operations or oversight of the Company's business (other than actions
resulting in a material diminution of the Executive's position or duties) shall
not constitute Good Reason under Section 3(c) of the Employment Agreement.

         2. Section 4(a)(i)(D) of the Employment Agreement is amended to read
hereafter as follows:

                  "D. effective as of the Date of Termination, (1) immediate
         vesting and exercisability of, and termination of any restrictions on
         sale or transfer (other than any such restriction arising by operation
         of law) with respect to, each and every stock option, restricted stock
         award, restricted stock unit award and other equity-based award and
         performance award (each, a "Compensatory Award") that is outstanding as
         of a time immediately prior to the Date of Termination and (2) the
         extension of the term during which each and every Compensatory Award
         may be exercised by the Executive until the earlier of (x) the first
         anniversary of the Date of Termination or (y) the date upon which the
         right to exercise any Compensatory Award would have expired if the
         Executive had continued to be employed by the Company under the terms
         of this Agreement until the Final Expiration Date.

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         3. Section 4(b) of the Employment Agreement is amended to read
hereafter as follows:

                  "(b) Death (except during a Window Period). If the Executive's
         employment is terminated by reason of the Executive's death during the
         Employment Period and other than during a Window Period in which event
         the provisions of Section 4(a) shall govern, this Agreement shall
         terminate without further obligations to the Executive's legal
         representatives under this Agreement, other than (i) the payment of
         Accrued Obligations (which shall be paid to the Executive's estate or
         beneficiary, as applicable, in a lump sum in cash within 30 days of the
         Date of Termination), (ii) the payment of an amount equal to the Annual
         Salary that would have been paid to the Executive pursuant to this
         Agreement during the Remaining Employment Period if the Executive's
         employment had not terminated by reason of death (which shall be paid
         to the Executive's estate or beneficiary, as applicable, in a lump sum
         in cash within 30 days of the Date of Termination) reduced by the
         amount payable in respect of Executive's death under any life insurance
         policy (other than accidental death and dismemberment or travel
         accident policies) but only to the extent such amounts are attributable
         to premiums paid by the Company, (iii) during the period beginning on
         the Date of Termination and ending on the first anniversary thereof
         medical benefits coverage determined as if Executive's employment had
         not terminated by reason of death, (iv) as soon as practicable
         following the fiscal year in which death occurs, payment of an amount
         equal to the product of (x) the Annual Bonus that would have been paid
         to Executive with respect to the year of termination had the Date of
         Termination not occurred and (y) a fraction, the numerator of which is
         the number of days in the fiscal year through the Date of Termination
         and the denominator of which is 365 and (v) effective as of the Date of
         Termination, (A) immediate vesting and exercisability of, and
         termination of any restrictions on sale or transfer (other than any
         such restriction arising by operation of law) with respect to, each and
         every Compensatory Award outstanding as of a time immediately prior to
         the Date of Termination and (B) the extension of the term during which
         each and every Compensatory Award may be exercised or purchased by the
         Executive until the earlier of (1) the first anniversary of the Date of
         Termination or (2) the date upon which the right to exercise or
         purchase any Compensatory Award would have expired if the Executive had
         continued to be employed by the Company under the terms of this
         Agreement until the Final Expiration Date.



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                  IN WITNESS WHEREOF, the Executive has hereunto set his hand
and, pursuant to the authorization from its Board of Directors, the Company has
caused these presents to be executed in its name on its behalf, all as of the
day and year first above written.

                                       CARRIZO OIL & GAS, INC.



                                       By:
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                                       By:
                                          --------------------------------------
                                           S. P. Johnson, IV