In a consecutive series of 146 patients with hepatocellular carcinoma (HCC), 10 patients (6.8%) were found to have one or two extrahepatic malignancies (EHM). Of these, eight had double cancers and two, triple cancers. The associated malignancies included eight cases of gastric cancer and four cases of colon cancer. Among the 12 lesions, eight were in the early stage. All the 10 patients were hepatitis B surface antigen negative. The incidence of coexisting liver cirrhosis and the retention rate of indocyanin green in 15 minutes among HCCs with EHM were significantly lower than those among HCC alone. These results suggest that the etiology of HCC with EHM is different from the etiology of HCC alone in Japan.