Between 1/85 and 1/90, 14 consecutive patients were entered into a prospective study of conventional adjuvant post-operative external beam radiotherapy after complete resection for a pancreatic adenocarcinoma. The surgical procedure was a Whipple resection in nine patients, a distal pancreatectomy in four patients and a total pancreatectomy in one patient. There were three T1b, eight T2 and three T3 tumours (UICC 1987); nodal involvement was present in five cases. The radiotherapy was delivered using a four-field box technique with a 23 x MV photon beam. All patients received a total dose of 54 Gy to the tumour bed. The mean treated volume was 900 cm3. Acute toxicities consisted mainly of weight loss (mean: 2 kg). Two patients had a grade 2 diarrhoea and two patients a grade 2 gastritis. Late effects were minimal and only observed in two patients. The overall locoregional recurrence (LR) rate was 50%. The median disease-free survival was 12 months, and the median survival was 23 months. This post-operative conventional radiotherapy treatment gives results that are comparable to the results of the GITSG-adjuvant study using a combination of split-course radiotherapy and 5-fluorouracil (5-FU).