Between 1971 and 1988 74 operations for intestinal complications following radiotherapy were performed on 67 patients at the Second Surgical Department, University of Vienna. The lesions were located in the small bowel (n = 41) and in the sigmoid colon/rectum (n = 33). 98.5% of the patients were females, the most frequent cause for irradiation being ovarian cancer. Bowel stenosis with resultant chronic or acute ileus was the most frequent indication for operation, occurring in 31 cases (76%) of the small bowel lesions and in 15 cases (46%) of the colon lesions. Percutaneous irradiation resulted in a significantly higher proportion of small bowel lesions (77%, p = 0.001), whilst endocavitary irradiation was followed in 67% of cases by colorectal lesions. Different application modality of irradiation also resulted in completely different symptoms for small and large bowel lesions. The operative mortality was 9.5%. Peritonitis following anastomotic leakage was the cause of death in 6 of 7 cases. In the treatment of small bowel ileus mortality following bowel resection (9%, one of 11 cases) was comparable to that of the bypass operation (6%, one of 18 cases). Both operation methods seem to be justified. Single-layer anastomosis resulted in zero mortality (21 cases) for ileus operation compared with 19% mortality (16 cases) in double-layer anastomosis and should be preferred for operations on the irradiated bowel.