Morbidity and mortality have been evaluated in 238 patients with acute large bowel obstruction admitted over a ten year period. In two thirds, the cause of obstruction was a primary colonic carcinoma. Most of these patients (61%) had advanced disease and were over 70 years of age. Volvulus and cancer recurrences each accounted for 10%, and diverticulitis for eight percent. An overall mortality of 24% was found. Of 115 patients who had the obstructing lesion--primary carcinoma or diverticulitis--resected, a mortality of 8.7 was seen, higher for primary (14.9%) than for staged (4.4%) resections, in contrast the latter had a significantly longer hospital stay, 30 days as against 17 days when a primary resection was performed. Six non-lethal anastomotic leaks occurred. It is concluded, that patients with large bowel obstruction, most often caused by a colorectal carcinoma, are a high-risk group. In this retrospective study staged procedure compared with primary resection had lowest morbidity and mortality.