Sporadic cases of hepatocellular carcinoma (HCC) originating from nonalcoholic steatohepatitis (NASH) have recently been reported. Thus, we investigated the prevalence of NASH in patients with HCC. A review of the clinical records of 481 patients who underwent liver resection for HCC in our department between January 1991 and December 2003 revealed only two (0.4%) patients with HCC associated with NASH. Both of these patients had noninsulin-dependent diabetes mellitus, and neither had a history of alcohol consumption or blood transfusion. All serologic markers for hepatitis B and C viruses were negative. Histological examination of the noncancerous hepatic tissue revealed NASH with moderate hepatic fibrosis in one patient and cirrhosis in the other. Thus, clinical follow-up and screening for HCC should be done for patients with hepatic fibrosis caused by NASH, even though this form of hepatitis is an uncommon cause of HCC.