Four cases of advanced hepatocellular carcinoma patients were treated by intra-portal infusion of 5-FU immediately after surgery. 5-FU at 120-250 mg daily was injected continuously via portal catheter from postoperative day 4 to 21. Two cases with short administration period of 4 days died of recurrence on the residual liver at 9 and 7 months after hepatic resection. Another 2 cases with a total amount of 5-FU at 2,165 mg and 2,250 mg, respectively, survived 4 years 3 months and 4 year 8 months each. Mild leukocytopenia and transient liver dysfunction were found as side effects. Intraportal infusion of anticancer drugs is a promising means to prevent intrahepatic micrometastasis after resection of hepatocellular carcinoma.