A survey of Japanese autopsy cases of primary biliary cirrhosis disclosed that hepatocellular carcinoma is apparently becoming a better recognized complication of the advanced stage of primary biliary cirrhosis. Six autopsy cases (five women and one man) of primary biliary cirrhosis associated with hepatocellular carcinoma were obtained from several Japanese institutions and examined. AU cases were in an established cirrhotic stage of primary biliary cirrhosis. Hepatocellular carcinoma was incidentally found at autopsy in four cases and, in these, the carcinomas were small in size and number. The other two cases showed advanced hepatocellular carcinoma and one case showed extrahepatic metastasis. Histologically, all cases showed well-differentiated hepatocellular carcinomas. Fatty changes or bile plugs were frequently seen within the tumors. Mallory body clusters and focal deposition of copper-binding protein were consistently found in cirrhotic liver tissues and also in the carcinoma tissues of almost all cases. The presence of atypical adenomatous hyperplasia in the peripheries of some carcinomas suggested that hepatocellular carcinoma in primary biliary cirrhosis may evolve through multiple steps. (HEPATOLOGY 1990; 11:lOlO-1016.) HCC is a frequent complication of most types of cirrhosis, especially cirrhosis of viral origins and hemochromatosis (1, 2). However, development of HCC has been reported to be uncommon or even rare in some types of cirrhosis, including PBC (1,3). In recent years, a few studies have been made on the occurrence of HCC in PBC, especially in the advanced cirrhotic liver (3-8). Melia et al. ( 5 ) reported that HCC was the cause of death in 33% of the men and 5% of the women studied who suffered from PBC. They suggested that, allowing for the marked predominance of women among the patients with PBC, HCC may be no less frequent in PBC than in other types of cirrhosis.