Forty-two patients with fixed inoperable adenocarcinoma of the rectum due to local extension in the pelvis have been treated using high dose radiotherapy followed by surgery when possible. Inoperability was determined initially by laparotomy in 15 patients and in the remainder by examination under anaesthetic. Twenty-nine patients underwent laparotomy following radiotherapy and resection was performed in 18. In three of these cases there was no residual tumour in the operation specimen. The median survival of the resected group was 28 months compared with 7 months for the unresected group. Treatment related mortality in the resected group was confined to five patients, two postoperative deaths and three small bowel fistulae which developed as late complications. Analysis of prognostic factors indicates that patients most likely to benefit from this approach are those with no evidence of distant metastases or of urinary obstruction at presentation. Patients who have a good clinical response to radiotherapy are more likely to achieve resection and subsequent long-term survival.