Exhibit 99.1

PRESS RELEASE       Contact:    Carrizo Oil & Gas, Inc.
                                B. Allen Connell, Director of Investor Relations
                                Paul F. Boling, Chief Financial Officer
                                (713) 328-1000


CARRIZO OIL & GAS, INC. ANNOUNCES FIRST QUARTER 2005 FINANCIAL RESULTS

HOUSTON,  May 10, 2005 -- Carrizo Oil & Gas, Inc. (Nasdaq:  CRZO) today reported
the Company's  financial  results for the first quarter of 2005,  which included
the following highlights:

o    Production of 2.35 Bcfe.

o    Revenue of $15.5 million.

o    Net Income of $2.6 million.

o    EBITDA, as defined below, of $10.6 million.

Revenues  for the three  months  ended  March 31,  2005 were  $15.5  million  as
compared to $10.9 million  during the quarter ended March 31, 2004. The increase
in  revenues  was driven by higher  prevailing  oil and  natural  gas prices and
higher natural gas production.  Production volumes during the three months ended
March 31, 2005 were 2.35 Bcfe as compared to 1.86 Bcfe during the first  quarter
of 2004 and  essentially  flat compared to our fourth  quarter 2004  production.
Carrizo's average oil sales price increased 52 percent to $50.65 per barrel from
$33.33 per barrel  during the first quarter of 2004,  while the average  natural
gas sales price increased four percent to $6.19 compared to $5.95 per Mcf in the
first  quarter of 2004.  The above  prices  include  the cash  effect of hedging
activities.

After  dividends  and  accretion  of discount on  preferred  stock,  the Company
reported net income  available to common shares ("Net  Income") of $2.6 million,
or $0.11 and $0.11 per basic  and  diluted  share,  respectively,  for the three
months ended March 31, 2005, as compared to $2.0 million, or $0.12 and $0.10 per
basic  and  diluted  share,  respectively,  for the same  quarter  during  2004.
Excluding  the $0.6  million  non-cash,  after-tax  impact of the  stock  option
compensation expense related to the employee stock options repriced in 2000, Net
Income for the quarter ended March 31, 2005 was $3.2 million, or $0.14 and $0.14
per basic and diluted share, respectively.

EBITDA  (earnings  before  interest,  income tax,  depreciation and amortization
expenses, and certain other non-cash items) during the first quarter of 2005 was
$10.6 million, or $0.47 and $0.45 per basic and diluted share, respectively,  as
compared  to $7.1  million,  or $0.43 and $0.37  per  basic and  diluted  share,
respectively, during the first quarter of 2004.



Oil and gas operating  expenses  (excluding  production taxes) increased to $1.3
million during the three months ended March 31, 2005 as compared to $1.0 million
for the first quarter of 2004,  largely due to the  increased  well count of the
Barnett Shale wells.

Depreciation,  depletion and  amortization  expenses  ("DD&A") were $4.7 million
during the three  months  ended  March 31,  2005 ($1.99 per Mcfe) as compared to
$3.2 million  ($1.74 per Mcfe) during the first quarter of 2004. The increase in
DD&A expense was due to an increase in the DD&A rate  primarily due to additions
to the proved property cost base.

General and administrative expenses ("G&A") increased to $2.6 million during the
three months  ended March 31, 2005 from $2.1 million  during the same quarter of
2004.  The increase in G&A was due  primarily to higher  incentive  compensation
costs of $0.3  million,  higher  base  salary  costs of $0.1  million and a $0.1
million increase in general office expenses.

Non-cash stock option compensation  expense was $1.0 million ($0.6 million after
tax)  for  the  three  months  ended  March  31,  2005.   This   represents  the
quarter-to-quarter  increase  in value  of  employee  stock  options  that  were
repriced in 2000.

Other income and expense for the first quarter of 2005 was a net expense of $0.2
million directly attributable to the non-cash equity in the loss of Pinnacle Gas
Resources,  Inc.  ("Pinnacle")  of $0.2  million  (both  before and after  tax).
Similarly,  other  income and  expense  for the first  quarter of 2004 was a net
charge of $0.2 million directly  attributable to the non-cash equity in the loss
of  Pinnacle.  Net  losses  are  expected  in this  early  phase  of  Pinnacle's
development of its coalbed methane play, and are expected to continue in 2005.

Interest  expense,  net of amounts  capitalized,  was $0.6 million for the three
months ended March 31, 2005 compared to an inconsequential  amount for the three
months  ended March 31,  2004.  The  increase is  directly  attributable  to the
maximum interest expense that is capitalizable  ("capitalizable interest") under
GAAP  which has  typically  been  equal to or  greater  than the gross  interest
expense (i.e.  interest expense before  capitalization  of interest  expense) in
each period.  Starting in the fourth quarter 2004,  the gross  interest  expense
exceeded  the  capitalizable   interest  by  an  amount   proportionate  to  the
outstanding debt in excess of our unproved property balance.

"The  highlights of 2005 to date were our 100 percent  drilling  success in both
the Gulf Coast (six wells) and Barnett Shale (12 wells),  and successful leasing
in the  Barnett  bringing  our total  acreage  position  to more than 50,000 net
acres,"  commented  S.P.  Johnson IV,  Carrizo's  President and Chief  Executive
Officer.  "Although our 2005 drilling activity started off slowly,  our activity
level is now back to a normal pace with three rigs running in the Gulf Coast and
two in the Barnett  Shale (one  vertical  and one  horizontal).  Two  additional
Carrizo  operated  horizontal rigs will be drilling at the end of May. The first
Carrizo operated  horizontal Barnett Shale well in Parker County,  Texas, the El
Chico #2,  began  flowing to sales last week at 3.0  MMcfe/d.  Carrizo  has a 65
percent working interest and additional drillsites on the lease."

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 and the Barnett Shale area in North



Texas.  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, the expected timing of
drilling of additional  wells 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, 2004 and its other  filings with the
Securities and Exchange Commission.

                        (Financial Highlights to Follow)



                             CARRIZO OIL & GAS, INC.
                            STATEMENTS OF OPERATIONS
                                   (unaudited)




                                                                                         THREE MONTHS ENDED
                                                                                            MARCH 31,
                                                                                ---------------------------------
                                                                                      2005             2004
                                                                                ---------------   ---------------
                                                                                            
Oil and natural gas revenues                                                     $  15,458,186     $  10,873,404
                                                                                ---------------   ---------------

Costs and expenses:
   Oil and natural gas operating expenses                                            1,265,310         1,000,814
   Production taxes                                                                    970,105           675,395
   Depreciation, depletion and amortization                                          4,677,838         3,246,596
   General and administrative expenses                                               2,600,454         2,132,508
   Accretion expense related to asset retirement obligations                            17,530             6,442
   Stock option compensation expense                                                   975,780             9,682
                                                                                ---------------   ---------------

Total costs and expenses                                                            10,507,017         7,071,437
                                                                                ---------------   ---------------


Operating income                                                                     4,951,169         3,801,967
                                                                                ---------------   ---------------

Other income and expenses, net                                                        (213,490)         (234,780)
Interest income                                                                         44,105            12,780
Interest expense, net of amounts capitalized                                          (608,464)          (43,397)
                                                                                ---------------   ---------------

Income before income taxes                                                           4,173,320         3,536,570
                                                                                ---------------   ---------------

Income taxes                                                                         1,587,080         1,353,148
                                                                                ---------------   ---------------

Net income                                                                           2,586,240         2,183,422
                                                                                ---------------   ---------------

Dividends and accretion of discount on preferred stock                                       -           197,995
                                                                                ---------------   ---------------

Net income available to common shares                                                2,586,240         1,985,427
                                                                                ===============   ===============

EBITDA, as defined (see table below)                                             $  10,630,738     $   7,073,692
                                                                                ===============   ===============

Basic net income per common share:                                               $        0.11     $        0.12
                                                                                ==============    ==============

Diluted net income per common share:                                             $        0.11     $        0.10
                                                                                ==============    ==============

Basic weighted average common shares outstanding                                    22,501,696        16,613,430
                                                                                ---------------   ---------------

Diluted weighted average common shares outstanding                                  23,402,248     $  19,284,153
                                                                                ---------------   ---------------


                                     (more)



                             CARRIZO OIL & GAS, INC.
                             CONDENSED BALANCE SHEET






                                                                                    03/31/05         12/31/04
                                                                                ---------------   ---------------
                                                                                           (unaudited)
                                                                                            
ASSETS:
  Cash and cash equivalents                                                      $   8,263,502     $   5,668,000
  Other current assets                                                              11,672,828        15,965,885
  Property and equipment, net                                                      211,817,920       205,482,585
  Other assets                                                                       1,635,718         1,689,447
  Investment in Pinnacle Gas Resources, Inc.                                         5,007,223         5,229,134
                                                                                ---------------   ---------------

TOTAL ASSETS                                                                     $ 238,397,191     $ 234,035,051
                                                                                ===============   ===============

LIABILITIES AND EQUITY:
  Accounts payable and accrued liabilities                                       $  25,077,283     $  30,682,970
  Current maturities of long-term debt                                                  88,213            89,653
  Long-term notes payable                                                           21,032,207        18,032,002
  Long-term subordinated notes payable, net                                         45,686,543        44,852,384
  Deferred income taxes                                                             18,719,731        18,112,950
  Other liabilities                                                                  1,477,911         1,406,567
  Equity                                                                           126,315,303       120,858,525
                                                                                ---------------   ---------------

TOTAL LIABILITIES AND EQUITY                                                     $ 238,397,191     $ 234,035,051
                                                                                ===============   ===============


(1)  Income tax expense  for the three  months  ended March 31, 2005  includes a
     $1,538,330  provision for deferred income taxes and a $48,750 provision for
     currently payable franchise taxes.  Income tax expense for the three months
     ended March 31, 2004 includes a $1,308,148  provision  for deferred  income
     taxes and a $45,000 provision for currently payable franchise taxes.

(2)  Long-term  subordinated  notes  payable are  presented  net of discounts of
     $1,862,381  and  $1,987,206  as of March 31, 2005 and  December  31,  2004,
     respectively.

(3)  Stock option  compensation  expense is a non-cash charge resulting from the
     change in the price of the stock  underlying  employee  stock  options that
     were repriced in February 2000.

(4)  In February  2002,  the  Company  consummated  the sale of $6.0  million of
     convertible  participating  preferred stock and warrants to purchase shares
     of  the  Company's  common  stock.  All of  the  convertible  participating
     preferred stock was converted into 1,318,125  shares of common stock during
     2004.

(5)  During the three and twelve  months  ended March 31, 2005 and  December 31,
     2004,  334,210 and  2,928,611  warrants  were  converted  into  304,669 and
     2,159,627 shares of common stock, respectively.

                                     (more)



                             CARRIZO OIL & GAS, INC.
                              NON-GAAP DISCLOSURES
                                   (unaudited)




                                                                                      THREE MONTHS ENDED
                                                                                            MARCH 31,
                                                                                ---------------------------------
Reconciliation of Net Income to EBITDA                                               2005              2004
- ---------------------------------------------------------------------           ---------------   ---------------
                                                                                             
Net income                                                                       $   2,586,240     $   2,183,422
                                                                                ---------------   ---------------

Adjustments:
  Depreciation, depletion and amortization                                           4,677,838         3,246,596
  Interest expense, net of amounts capitalized and interest income                     564,359            30,617
  Income taxes                                                                       1,587,080         1,353,148
  Equity in Pinnacle Gas Resources, Inc.                                               221,911           243,785
  Stock Option compensation expense (benefit)                                          975,780             9,682
  Accretion expense related to asset retirement obligations                             17,530             6,442
                                                                                ---------------   ---------------

EBITDA, as defined                                                               $  10,630,738     $   7,073,692
                                                                                ===============   ===============

EBITDA per basic common share                                                    $        0.47     $        0.43
                                                                                ===============   ===============

EBITDA per diluted common share                                                  $        0.45     $        0.37
                                                                                ===============   ===============


                             CARRIZO OIL & GAS, INC.
                          PRODUCTION VOLUMES AND PRICES
                                   (unaudited)



Production volumes-

                                                                                            
    Oil and condensate (Bbls)                                                           64,784            87,123
    Natural gas (Mcf)                                                                1,965,958         1,338,776
    Natural gas equivalent (Mcfe)                                                    2,354,662         1,861,514

Average sales prices-

    Oil and condensate (per Bbl)                                                 $       50.65     $       33.33
    Natural gas (per Mcf)                                                        $        6.19     $        5.95
    Natural gas equivalent (per Mcfe)                                            $        6.56     $        5.84



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