The routine use of isoniazid prophylaxis after liver transplantation is a controversial issue because the benefits must be weighed against the risk of hepatotoxicity. We decided not to institute isoniazid prophylaxis but to study the efficacy of a surveillance mycobacterial program. One hundred patients were included in the protocol. Sputum and urine samples were processed before transplantation and on days 15, 30, 60, 90, 12, 150, and 180 for acid-fast stain and culture. One case of tuberculosis was promptly identified and successfully treated. Cases of tuberculosis with negative surveillance cultures were not identified. Our approach indicates that surveillance mycobacterial cultures can permit rapid identification of tuberculosis after liver transplantation and it is an alternative for groups who questioned isoniazid prophylaxis.