Twenty-two patients with hepatocellular carcinoma were treated by a new method of transcatheter arterial chemoembolization using an autologous blood clot as an embolizing agent. All had underlying advanced cirrhosis (14 Child's class B and 8 Child's class C patients). The median follow-up interval was 11 mo (range = 2 to 30 mo). The results of the treatment were compared with those of conventional chemoembolization using gelatin sponge particles for 19 Child's class B patients as historical controls. The survival rate for Child's class B patients treated by the new procedure estimated by the Kaplan-Meier method was 100% at 2 yr, whereas the survival rate for Child's class B patients treated by conventional chemoembolization was 89% at 1 yr and 72% at 2 yr. The survival rate for Child's class C patients was 75% at 1 yr and 50% at 2 yr. Side effects such as pyrexia of more than 38 degrees C or an elevation of the serum bilirubin level of more than 1.5-fold were less common in patients treated by the new method than in those treated by conventional chemoembolization, and thus the new procedure could be performed even for Child's class C patients. The autologous blood clot did not collapse the hepatic arteries even when the embolization was performed repeatedly, and thus fine collateral vessels feeding recurrent hepatocellular carcinoma did not develop. The results suggest that the new chemoembolization using an autologous blood clot is a promising therapeutic procedure in the management of hepatocellular carcinoma associated with advanced cirrhosis.