Treatment results for 37 patients with localized pancreatic carcinoma treated using electron beam intraoperative radiation therapy (EBIORT) with curative intent from 1978 to 1990 in National Shikoku Cancer Center Hospital and the related hospitals were presented in comparison with those of a control group comprising 40 patients treated with no use of EBIORT. With additional treatment of EBIORT, 37 patients survived longer than the control 40 patients (p less than 0.05 during the 19th and 31st month). In the macroscopically total or partial resection, patients treated with EBIORT survived slightly longer than the controls. In the unresectable lesions, patients treated with EBIORT survived longer than the control patients (p less than 0.05 during the 7th month). In this group, there was one 5-year survivor who received EBIORT plus postoperative external radiation therapy (ERT) to the unresectable pancreatic head lesion but died 5 years later of massive bleeding from the duodenal ulcerations. Patients with unresectable carcinoma treated by EBIORT plus ERT survived longer than patients treated with EBIORT alone (p = 0.065). Pain relief was obtained in 95.0% of the unresectable patients with pain. Major adverse effects caused by irradiation were gastrointestinal troubles in five patients (leakage of choledochojejunostomy, gastric ulcerations, duodenal stenosis, gastric ulcerations and duodenal stenosis, duodenal perforation and ulcerations). EBIORT proved to be effective in the relief of serious pain and in the improvement of the survival of patients with localized pancreatic carcinoma.