From 1972 to 1981, 7 patients received adjuvant external beam radiation therapy before (5 patients) or after (2 patients) a curative Whipple operation for adenocarcinoma of the pancreas (5 patients) or ampulla of Vater (2 patients). Via supervoltage, 4000-4520 rad/20-25 fractions/4-5 1/2 weeks were delivered to the tumor bed and draining lymphatics. Two patients (of 4 at risk) are 5-year survivors; 3 are alive-without-disease at 1-2 years follow-up. Distant metastases have developed to date in 3 patients. A marginal miss occurred at the edge of radiation portal in 1 patient, and no true in-field failures have occurred. Complications occurred in 2 patients. Because of the high incidence of local-regional failures after curative surgery alone for adenocarcinoma of the pancreas or ampulla of Vater, the above results suggest that adjuvant radiation therapy should be considered as a modality to potentially improve treatment results.