Sigmoidectomy was performed for a 69-year-old man with sigmoid colon cancer and unresectable multiple liver metastases. The histological diagnosis was undifferentiated carcinoma of sigmoid colon. Hepatic arterial infusion chemotherapy with 5 FU and systemic chemotherapy with CPT-11 were performed after the operation. A complete response (CR) was achieved for liver metastases. The recurrent sign was not found at 23 months after the operation. This combination therapy is expected to be an alternative treatment of colorectal cancer with unresectable multiple liver metastases.