OBJECTIVE Hepatitis C virus (HCV) is the most common cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. It is controversial whether HCV causes fulminant hepatitis. METHODS To determine the clinical features and etiology of acute hepatitis and fulminant hepatitis in Japan, an endemic area of hepatitis C, between 1986 and 2001 inclusively, a retrospective study of consecutively referred patients was performed. Two hundred and sixty-three patients admitted to a liver clinic after diagnosis of acute hepatitis or fulminant hepatitis, were evaluated. RESULTS We found 181 cases of acute hepatitis and 82 cases of fulminant hepatitis/late onset hepatic failure. No cases of fulminant hepatitis were positive for HCV RNA. Only three cases had positive anti-HCV antibody, and they were thought to indicate past HCV infection. The main cause of infection in these three patients was hepatitis A virus in one,hepatitis B virus in one, and drugs in the remaining one. HCV did not seem to be the major cause. The three cases died without receiving liver transplantation. CONCLUSIONS It was revealed that fulminant hepatitis C rarely occurs in Japan, as well as in the USA and European countries. Investigators should search for other causes in fulminant cases presenting an HCV marker.