Thirteen patients with unresectable liver tumors, including 7 colorectal cancers, 5 gastric cancers, and 1 breast cancer, were treated by intraarterial continuous infusion of CDDP using an implantable reservoir. The catheter was placed by direct insertion at laparotomy (7 cases) or through the inferior epigastric artery (6 cases). The clinical antitumor effects were evaluated by CT-scan or ultrasonography. One CR, 6 PR, and 6 NC were observed among the thirteen patients, respectively. The response rate for all cases was 53.8%, which is evidently higher than that of previously reported "one shot" transarterial MMC and 5-FU infusion chemotherapy. Since this treatment method induces little side effects, it can be maintained in outpatient clinics. Thus, we concluded that this treatment could be useful to improve the quality of life of patients with unresectable liver tumors.