To determine the feasibility of high dose radiotherapy and to evaluate its role in the management of extrahepatic bile duct (EHBD) cancer. Between 1983 and 1991, 145 consecutive patients with EHBD cancer were treated by low dose rate intraluminal 192Ir irradiation (ILRT) either alone or in combination with external beam radiotherapy (EBRT). Among the primarily irradiated, 77 patients unsuitable for surgical resection, 54 were enrolled in radical radiotherapy, and 23 received palliative radiotherapy. Fifty-nine received postoperative radiotherapy, and the remaining 9 preoperative radiotherapy. The mean radiation dose was 67.8 Gy, ranging from 10 to 135 Gy. Intraluminal 192Ir irradiation was indicated in 103 patients, and 85 of them were combined with EBRT. Expandable metallic biliary endoprosthesis (EMBE) was used in 32 primarily irradiated patients (31 radical and 1 palliative radiotherapy) after the completion of radiotherapy. The 1-, 3-, and 5-year actuarial survival rates for all 145 patients were 55%, 18%, and 10%, for the 54 patients treated by radical radiotherapy (mean 83.1 Gy), 56%, 13%, and 6% [median survival time (MST) 12.4 months], and for the 59 patients receiving postoperative radiotherapy (mean 61.6 Gy), 73%, 31%, and 18% (MST 21.5 months), respectively. Expandable metallic biliary endoprosthesis was useful for the early establishment of an internal bile passage in radically irradiated patients and MST of 14.9 months in these 31 patients was significantly longer than that of 9.3 months in the remaining 23 patients without EMBE placement (p < 0.05). Eighteen patients whose surgical margins were positive in the hepatic side bile duct(s) showed significantly better survival compared with 15 patients whose surgical margins were positive in the adjacent structure(s) (44% vs. 0% survival at 3 years, p < 0.001). No survival benefit was obtained in patients given palliative or preoperative radiotherapy. Gastroduodenal complications increased in those receiving doses of 90 Gy or more, and serious biliary bleeding was experienced in three preoperatively irradiated patients. Complications in other patients was tolerable. High-dose radiotherapy, consisting of ILRT and EBRT, appears to be feasible in the management of EHBD cancer, and it offers a survival advantage for patients not suited for surgical resection and patients with positive margins in the resected end of the hepatic side bile duct. Expandable metallic biliary endoprosthesis assists the internal bile flow and may lengthen survival after high dose radiotherapy.