In colorectal cancer, liver metastasis is the most common and most important prognostic factor. Although surgical resection is the first choice of treatment for liver metastasis of colorectal cancer, there are many cases we cannot choose the surgical treatment. The chemotherapy is very important in such cases. We examined 18 cases of unresectable liver metastases from colorectal cancer which were adapted a hepatic arterial infusion of 5-FU (HAI) with a weekly high-dose infusion method (WHF) as the first-line treatment, and then systemic chemotherapy of CPT-11 in combination with 5-FU as the second-line treatment. The response rate of this treatment is 72% (13/18) and the 1-, 2-, 3-year survival rates were 100% (16/16), 83% (10/12), and 50% (5/10), respectively. The combination chemotherapy of HAI with systemic chemotherapy using CPT-11 seemed to be an effective treatment method.