EXHIBIT 23.1 Consent of Independent Auditors We consent to the incorporation by reference in the Registration Statements (Form S8 No. 333-35245 and No. 333-55838) pertaining to the Incentive Plan of Carrizo Oil & Gas, Inc. of our report dated March 25, 2004, with respect to the consolidated financial statements of Carrizo Oil & Gas, Inc. included in the Annual Report (Form 10-K) for the year ended December 31, 2003. ERNST & YOUNG LLP Houston, Texas March 29, 2004