A 70-year-old male patient presented with cirrhotic liver caused by hepatitis C virus and complicated with hepatocellular carcinoma. The carcinoma was effectively treated by transarterial chemoembolization, but cholangiocellular carcinoma occurred in a different segment of the liver and rapidly grew and metastasized systemically. He died 13 months after the first admission. Double cancer of the liver is uncommon, but it must be considered in the differential diagnosis of cases of hepatocellular carcinoma associated with chronic hepatitis or cirrhosis. Failure to note the occurrence of cholangiocellular carcinoma is thought to be a diagnostic pitfall in the follow-up studies of patients with hepatocellular carcinoma.