A study was made of 50 consecutive patients with duodenal ulcers that were complicated to a degree warranting surgical intervention, but were treated by gastric irradiation instead of operation. After the course of treatment, the patients were permitted complete freedom from medication and dietary restrictions. In the survey made 2 to 8 1/2 years after treatment, 27 patients were found completely free of ulcer disease and 11 had very mild symptoms reminiscent of their ulcer. The results were classified as fair in 1 case and as failures in 11 cases. Among the 11 failures were 6 cases in which gastric resection ultimately became necessary. The remaining 5 patients had had recurrent ulcers but were able to control the symptoms with a medical program.