We studied the histopathological changes of liver in four patients who developed hepatomegaly and abnormal liver chemistry tests 2 to 20 days following administration of L-asparaginase as a part of a combination chemotherapy regimen for treatment of acute lymphoblastic leukemia. The severity of the liver disease due to L-asparaginase was unpredictable. One patient developed acute fulminant hepatic failure and required liver transplantation. The most consistent pathological change, observed in all four cases, was diffuse steatosis. Other changes included patchy hepatocyte necrosis, mixed inflammatory cell infiltrates in the portal tracts, and variable degrees of hepatocellular, or canalicular cholestasis, or a combination of these.