A cooperative group study was carried out on the effect of Lipiodol transcatheter arterial chemo-embolization (L-TACE) for non-resectable hepatocellular carcinoma (HCC). Thirty-seven hospitals in Japan participated in this study and a total of 157 eligible patients included 138 males and 19 females with an average age of 60.3 y.o. In the chemo-embolization, Lipiodol mixed with 20-50 mg/m2 of doxorubicin (adriamycin) was given through a catheter, and this was followed by embolization with gelatin sponge. Effect of additional oral 5-FU (150-200 mg/day) was also studied as an open trial. Levels of serum alpha-feto protein decreased at 10 days after L-TACE, and this decrease lasted for 5 weeks. CR was observed in one patient, PR in 33, MR in 24, NC in 66 and PD in 16. The response rate was 24.3%. Cumulative one-year, two-year and three-year survival rates were 56.0%, 30.8% and 26.4%, respectively. It was concluded that higher survival rates after L-TACE were observed when (1) patients had better functional reserves of the liver, (2) HCC was in the less advanced stage and (3) L-TACE was carried out more than twice. A reduction of the tumor size after L-TACE did not necessarily mean a good prognosis for the patients. There was no significant difference in the survival rate between the patients taking or not taking 5-FU.