This study was designed to evaluate whether intraarterial and intra-portal infusion chemotherapy was effective in 57 patients with liver metastases from colorectal cancer and 10 from gastric cancer. Arterial infusion was effective to prevent recurrence in the remnant liver after resection of liver metastases from colorectal cancer. On the other hand, intra-portal infusion was not effective to prevent recurrence. In the patients with unresectable metastases, arterial infusion was also effective for the response rate, which was 75% (with intra-portal infusion) and 27 % (arterial infusion only), respectively. However, arterial infusion had no effect in patients with metastases from gastric cancer. As a result, arterial infusion was effective to prevent recurrence after resection of metastases, and to increase the survival rate in patients with unresectable metastases from colorectal cancer.