A total of 22 patients with cholangiocarcinoma who had been treated with external radiotherapy between 1978 and 1989 were analyzed. Of the 22 patients, 18 had cancer of the hepatic hilus (Klatskin) and 4 had intrahepatic biliary cancer; all but 2 of the subjects had advanced disease. In all, 16 patients underwent primary irradiation for unresectable tumors, 4 were subjected to adjuvant irradiation after gross tumor resection, and 2 received preoperative irradiation followed by gross tumor resection. The mean initial irradiation dose was 52.0 Gy (range, 26-78 Gy). The TDF (time-dose-fractionation) for the entire course of radiotherapy ranged from 49 to 154 (mean, 100). The median survival of all patients was 10 months, and the cumulative 1-year survival value was 37.7%. The external radiotherapy proved to be effective in the treatment of cholangiocarcinoma in terms of palliation and survival.