Ten consecutive adults with localized nonresectable hepatocellular carcinomas were selected as a nonrandom sample for an investigation into the effectiveness of cisplatin (DDP) as a single agent when administered regionally via the hepatic artery from 1981 to 1984. The dose of DDP was 50 mg/m2 (normally, 80 mg). Complete remission (CR) was observed in one patient, partial remission (PR) in three patients, and in five patients, there were no significant changes in tumor size; the disease progressed in one patient. The mean period of survival of the group was 19.7 months. All patients suffered from severe nausea and vomiting, ordinarily until the afternoon of the day after treatment. One patient died of uremia, which related to the cytostate. The authors consider cisplatin useful in the intra-arterial treatment of hepatocellular carcinoma with favorable prognostic factors in patients for whom surgical treatment is not suitable.