The treatment of patients with liver metastasis from colorectal cancer was evaluated. Although surgical resection was the most effective therapy and 5-year survival was 30%, more than two-thirds of the patients were judged unresectable at the beginning of the treatment. Those whose metastasis was judged to be unresectable received hepatic arterial infusion (HAI) of 5-FU therapy. In a comparison of the survival period, patients received more than 15 g of 5-FU were found to have a statistically significant longer survival than those who received less than 15 g. Even though the patients who revealed a PR or CR response with HAI did not survive more than 4 years, we began surgical resection in these patients after HAI therapy. As a result, the 5-year survival rate of patients whose metastasis was unresectable and who underwent surgical resection after successful HAI was 30% which was equal to the result of the patients judged resectable at the beginning of the treatment. Such treatment may become the fundamental treatment for unresectable liver metastasis in the near future.