Seventy-four patients with clinically resectable adenocarcinoma of the rectum were treated with preoperative irradiation and surgery at the University of Florida between August 1975 and February 1982. All patients have been folloved for at least five years. Between 1975 and 1978, 29 patients received 3500 cGy; thereafter the dose was increased to 4000 to 5000 cGy for the remaining 45 patients. All patients were treated at 180 cGy per fraction. Following preoperative irradiation, 65 of 74 patients (88 percent) underwent complete resection of their lesions. Compared with a series of historical controls treated with surgery alone, the local recurrence rate at five years was 5 of 65 (7.7 percent)vs. 39 of 135 (29 percent) (P=.001), and the five-year absolute survival was 43 of 65 (66 percent)vs. 51 or 135 (38 percent) (P<.001). The local recurrence rate was 13 percent for patients receiving 3500 cGy and 5 percent for doses of 4000 to 5000 cGy. There was no apparent increased incidence in postoperative complications in the preoperatively irradiated patients. © 1988 American Society of Colon and Rectal Surgeons.