The therapeutic effectiveness of transcatheter arterial embolization (TAE) with intraarterial infusion of cisplatin/ethiodized oil mixture in treatment of resectable and unresectable hepatocellular carcinoma was compared with TAE with intraarterial infusion of doxorubicin mixed with and without ethiodized oil. The series included 97 patients with unresectable hepatocellular carcinoma and 40 patients with resectable hepatocellular carcinoma. With TAE using doxorubicin infusion, a partial response of the tumor was seen in only 11%, and the 2-yr survival was calculated to be only 5%. Histologic examination of the specimens obtained by hepatectomy also showed that this treatment was relatively ineffective in daughter tumor and portal tumor thrombi. In contrast, TAE with infusion of cisplatin/ethiodized oil mixture significantly increased the rate of partial response (38%), and significantly prolonged the 2-yr survival (45%). Histologically this treatment gave severe necrosis in daughter tumors (69%) and tumor thrombi (78%) as well as main tumor (75%). This treatment was significantly better than TAE with doxorubicin and ethiodized oil infusion in terms of the tumor regression and histologic responses of main tumor and portal vein tumor thrombi, but not in terms of the 2-yr survival. However, 2 patients (8%) died within 4 wk of the latter treatment, whereas no deaths were reported after the former treatment. Therefore, TAE combined with intraarterial infusion of cisplatin/ethiodized oil mixture may be a safe and useful treatment modality for hepatocellular carcinoma.