A 61-yr-old man with chronic myelocytic leukemia treated continuously for 8 yr with busulfan presented with fever, abdominal pain, and elevated liver enzymes in a cholestatic pattern. Evaluation of his liver and biliary tract with ultrasound and computerized tomography disclosed no structural abnormality. A percutaneous needle liver biopsy revealed cellular cholestasis with focal liver cell necrosis accompanied by a mild inflammatory infiltrate. Busulfan was discontinued, with subsequent normalization of liver enzymes and resolution of fever. These findings are interpreted as being compatible with busulfan-induced hepatitis.