Nonalcoholic steatohepatitis (NASH) was originally believed to be a benign disease. However, it has been recently revealed that NASH could lead to irreversible liver disease in some patients. We report an unusual case of hepatocellular carcinoma (HCC) in a 76-year-old man with NASH. He had no history of alcohol consumption, drug use, or blood transfusion. He was negative for all serological viral markers and autoantibodies. In addition, he was obese (body mass index [BMI], 30.75 kg/m(2)) and had type 2 diabetes mellitus. A liver biopsy specimen showed moderate steatosis with necroinflammatory changes, ballooning degeneration, Mallory bodies, pericellular fibrosis, and evidence of nodular regeneration. He was diagnosed with NASH with cirrhosis. Simultaneously, a liver tumor, measuring 19 mm in diameter, was detected in segment 6. A tumor biopsy specimen revealed well-differentiated HCC, and imaging modalities confirmed the characteristics of HCC. To our knowledge, ten patients who had HCC with NASH were reported. In all patients with NASH and HCC, cirrhosis was present. Patients with NASH and cirrhosis may progress to HCC, and regular screening, based on tumor markers and imaging modalities, is needed to detect HCC in patients with NASH and cirrhosis.