The efficacy of transarterial immuno-embolization therapy (TIE) was examined in six operable patients with hepatocellular carcinoma (HCC). We administered OK-432, fibrinogen (30 mg/ml) and thrombin (1 U/ml) through a catheter which was inserted into the tumor-feeding artery. In all patients with a high level of tumor markers (AFP and PIVKA-II), the level decreased promptly to less than the pretreatment level after TIE therapy. The therapy has not caused any serious side effects. No disturbance of the coagulation-fibrinolysis system due to TIE was observed in any patient. Histological examination of resected specimens following TIE showed massive infiltration of mononuclear cells around tumor cell nests, and lytic necrosis as well as coagulation necrosis of the main tumor and the intrahepatic metastases. Our results indicate that TIE may be an effective and promising modality for HCC patients.