SM-11355, a lipophilic platinum derivative, is a novel intra-arterial chemotherapeutic agent for hepatocellular carcinoma (HCC). A phase II study of SM-11355 was conducted to evaluate the antitumor activities and the toxicity in chemotherapy-naive patients with HCC. Sixteen patients were treated with transcatheter arterial injection of SM-11355-lipiodol emulsion (20-120 mg/body). The responses were evaluated by computed tomography 3 months after treatment. Complete response (CR) was defined as disappearance or 100% necrosis of all tumors, and lipiodol accumulation in tumors was regarded as indicating necrosis. Nine patients achieved CR (56%; 95% confidence interval, 29.9-80.2%). The grade 3 toxicities were neutropenia (19%), total bilirubin elevation (19%), AST elevation (44%), and ALT elevation (19%). None of the patients showed grade 4 toxicities or episodes of renal dysfunction. Other common adverse effects were eosinophilia (100%) and pyrexia (94%). Intra-arterial chemotherapy with SM-11355, which was well tolerated, showed promising antitumor activity in patients with HCC.