Intraoperative radiotherapy (IORT) with an electron beam is a therapeutic modality employed predominantly in tumours with a high risk of local recurrence. In this department 35 patients with proven adenocarcinoma of the pancreas underwent surgery and IORT, while 41 patients underwent surgery only. Irradiated patients suffered more serious postoperative complications (21 per cent versus 7 per cent), spent more time in hospital (32 days versus 26 days) and did not show a survival advantage (median of 326 days versus 366 days for two patients with curative resection). Anastomotic breakdown (twp patients), abscess formation (two patients) and pancreatitis in the pancreatic remnant (one patient) occurred only in this group. It is concluded that IORT may increase the risk of postoperative complications. As, on the basis of experimental data, an additional serious long-term risk is to be expected, application of IORT should be limited to well controlled study conditions.