PURPOSE: To evaluate the therapeutic efficacy of intra-arterial infusion of Cis-Diamminedichloroplatinum (C-DDP) for the treatment of hepatocellular carcinomas with widespread involvement. MATERIALS AND METHODS: We retrospectively analyzed 22 patients who between July 1994 and June 1996 had undergone intra-arterial c-DDP infusion therapy for the treatment of hepatocellular carcinomas with widespread involvement. The hepatomas involved both lobes in ten, portal venous obstructions in fourteen, arterio-portal shunts in nine, and arterio-venous shunts in two. Proper hepatic artery was selected for infusion of 100mg/BSA of C-DDP. The same procedure was repeated every 3 to 4 weeks, and the total number of infusions was 65. On the basis of WHO criteria, response was classified as complete remission, partial remission, stable, or progression of the disease. Six-month and one-year survival rates were estimated, and adverse reactions were evaluated. RESULTS: Complete remission was noted in one patient (4.5%) and partial remission in three (13.6%), while 18 showed no response or progression after treatment. The six month survival rate was 59.1%, and the one-year survival rate was 32.1%. Adverse reactions included nausea/vomiting (59.8%), abdominal pain (9.2%), fever (8.0%), acute renal failure (2.3%) and hepatic encephalopathy (1.1%). These adverse reactions were, however, transient and reversible. CONCLUSION: Although the response rate is not high, intra-arterial C-DDP infusion therapy can be used as an alternative treatment for hepatocellular carcinomas with widespread involvement; adverse reactions are tolerable.