With advances in surgical techniques, the number of curative resection for hilar cholangiocarcinoma has increased. However, the recurrence rate after curative resection is significantly high. There is no established adjuvant therapy for these patients, although some groups have administered intraarterial infusion of 5-fluorouracil combined with cisplatin. In our institution, postoperative radiation is administered to control remnant tumors at the ductal and surgical margins. Extracorporeal radiation is directed at the surgical margins and intraluminal radiation at the ductal margins. This has improved the cumulative survival rate for cholangiocarcinoma patients who underwent both curative and noncurative resection. The 3-year survival rate of those who underwent curative resection with and without postoperative radiation is 100% and 28.5%, respectively. The longest survival duration among our patients who received intraluminal radiation for positive ductal margins were 55 months. Because the biological behaviour and radiation sensitivity of the tumors differ among individually, these should be determined through molecular biologic studies in the future. Such tailored therapy will require multidisciplinary treatment.