EXHIBIT 16.1 April 12, 2002 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Dear Sir/Madam: We have read the second and third paragraphs of Item 4 included in the Form 8-K dated April 12, 2002 of Carrizo Oil & Gas, Inc. to be filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, ARTHUR ANDERSEN LLP Copy to: Mr. Frank J. Wojtek, Vice President, Chief Financial Officer and Secretary