Radiation treatment is playing an increasing role in the management of patients with ano-rectal carcinoma. This role may be categorized as a) adjuvant therapy of rectal cancer, b) definitive irradiation of rectal cancer, and c) radiotherapy of carcinoma of the anal canal. Preoperative irradiation according to a well-planned protocol is able not only to decrease the incidence of local failures but also to convert some tumors, initially suitable for AP resection, into a conservative procedure. Applied to selected cases, intracavitary irradiation can control limited rectal cancer with a rate higher than other conservative methods (series of 231 cases followed more than five years). Carcinoma of the anal canal should not be treated by radical surgery or by external beam irradiation alone. New approaches based on combined procedures such as cobalt-60 and iridium-192 implant, with or without chemotherapy, demonstrated a substantial improvement in five-year survival rates in a series of 100 cases. Proctology represents for the radiation oncologist an experience which is both gratifying and full of promise.