EXHIBIT 99.1

PRESS RELEASE       Contact:    Carrizo Oil & Gas, Inc.
                                B. Allen Connell, Director of Investor Relations
                                Paul F. Boling, Chief Financial Officer
                                (281) 496-1352

CARRIZO OIL & GAS, INC. ANNOUNCES SECOND QUARTER PRODUCTION UP 20 PERCENT OVER
2Q 2003 AND UPDATES DRILLING RESULTS; BARNETT SHALE TREND ACREAGE INCREASED 67
PERCENT DURING 2Q

HOUSTON, August 2, 2004 - Carrizo Oil & Gas, Inc. (Nasdaq: CRZO) today announced
the operating results for the second quarter of 2004. In Carrizo's core area in
South Texas and Louisiana, the Company participated in the drilling of 12 gross
exploratory wells, eleven of which were successful, resulting in a 92 percent
apparent success rate for the quarter. Eight of these successful wells have been
completed and three wells are in the process of being completed. As of the end
of the second quarter, five completed wells were waiting on connection to
pipelines. Drilling operations are currently underway on two additional wells.
Through the first half of the year, Carrizo has now drilled 21 wells, 17 of
which have been successful for an apparent 81 percent success rate in South
Texas and Louisiana. In the Company's Barnett Shale play in North Texas, Carrizo
participated in the drilling of eleven gross wells in the second quarter, all of
which were successful. Four of these successful wells have been completed and
seven are in the process of being completed. As of the end of the second
quarter, six completed Barnett Shale wells were waiting on pipeline connection.
Drilling operations are currently underway on three additional wells. Since the
beginning of the year, Carrizo has now drilled 19 Barnett Shale wells, all of
which were successful.

Production during the second quarter of 2004 was estimated to be 1.99 Bcfe, or
18 percent above the 1.68 Bcfe of production in the second quarter of 2003.
Second quarter 2004 production was up seven percent from the previous quarter.

Estimated production during the first half of 2004 has reached a level of 3.85
Bcfe or six percent above the 3.62 Bcfe of production in the first half of 2003.

Natural gas comprised 75 percent of total second quarter 2004 production
equivalent. Carrizo estimates that second quarter 2004 sales prices averaged
approximately $6.08 per Mcf and $35.27 per barrel. These prices include the
effects of hedging activities, which resulted in a decrease of the realized
price of natural gas by approximately $0.20 per Mcf and a decrease in the
realized price of



oil by approximately $2.22 per barrel. The oil sales price reflects the large
volume of condensate production relative to total oil production.

Operating highlights during the second quarter of 2004 and recent activity
include the following:

     o    As previously announced, in the West Coffee Bay Prospect in Lafourche
          Parish, Louisiana, the Company has successfully drilled the LL&E #1
          and logged an estimated 70 feet of apparent net pay in the Coffee Bay
          Sand. The well was deepened and another 16 feet of sand below the
          Coffee Bay Sand was found. This deeper 16 feet of sand has now been
          tested at a rate of approximately 7,319 Mcf and 249 barrels of
          condensate (8,813 Mcfe) per day. Pipeline facilities are currently
          being constructed and it is expected that the LL&E #1 will be put on
          production in early September. Carrizo is the operator of the well and
          owns a 47 percent working interest.

     o    The LL&E #2 well in Lafourche Parish, Louisiana, was drilled to total
          depth and logged during the second quarter. The deepest target was not
          successful and the Company is in the process of testing and completing
          the well in a secondary objective at approximately 12,000 feet.
          Carrizo is the operator of the LL&E #2 and owns a 60 percent working
          interest.

     o    Carrizo is currently drilling two wells in the Gulf Coast area:

          The Savage A-74 #1 well in Matagorda County, Texas, is currently
          drilling below 13,000 feet. Carrizo is the operator of the well and
          owns a 52.5 percent working interest.

          The LBLD #1 well in Carrizo's Bay de Chene Prospect, Lafourche Parish,
          Louisiana, is currently drilling below 9,000 feet. Carrizo is the
          operator of the well and owns a 50 percent working interest.

     o    In the Barnett Shale Trend in North Texas, Carrizo increased its
          position from 7,500 net acres to 12,500 net acres during the second
          quarter, a 67 percent increase. Currently, Carrizo has 13,500 net
          acres and 30 wells producing.

"We are slightly ahead of our plan to drill 40 wells in our onshore Gulf Coast
core area in 2004," commented S.P. Johnson IV, Carrizo's President and Chief
Executive Officer. "We anticipate a solid production increase when the five Gulf
Coast wells, waiting on pipeline hook-up, begin producing, especially the LL&E
#1. Our Barnett Shale program is growing rapidly in terms of acreage and reserve
potential, both in the core and non-core areas of the Barnett Shale Trend. We
plan to continue our aggressive drilling program in both the Gulf Coast and
Barnett Shale areas to take advantage of the current business environment."

Carrizo Oil & Gas, Inc., is a Houston-based energy company actively engaged in
the exploration, development, exploitation and production of oil and natural gas
primarily in proven onshore trends along the Texas and Louisiana Gulf Coast
regions. Carrizo controls significant prospective acreage blocks and utilizes
advanced 3-D seismic techniques to identify potential oil and gas reserves and
drilling opportunities.




Statements in this news release, including but not limited to those relating to
the Company's or management's intentions, beliefs, expectations, hopes,
projections, assessment of risks, estimations, plans or predictions for the
future including potential effects or timing, cash flow, reserve growth and
shareholder value, the expected timing of drilling of additional wells, the
completion testing of the LL&E #1 and LL&E #2 wells, plans for the drilling
program and other statements and other statements that are not historical facts
are forward looking statements that are based on current expectations. Although
the Company believes that its expectations are based on reasonable assumptions,
it can give no assurance that these expectations will prove correct. Important
factors that could cause actual results to differ materially from those in the
forward looking statements include the results and dependence on exploratory
drilling activities, operating risks, oil and gas price levels, land issues,
availability of equipment, weather and other risks described in the Company's
Form 10-K for the year ended December 31, 2003 and its other filings with the
Securities and Exchange Commission.