Forty previously undiagnosed cases of acute sigmoid volvulus presenting over five years in Nottingham are retrospectively reviewed. The average age was 71.6 years with an even sex ratio. Fifteen (38%) patients lived in nursing homes or institutions. At presentation, all had clinical features of large bowel obstruction, confirmed on plain abdominal X-ray. Sigmoidoscopy and rectal tube decompression was successful in 23 cases. The remaining 17 patients were treated surgically, within 24 hours, at which time the sigmoid was sutured to the abdominal wall (2 cases), resected and brought out as a colostomy (10 cases) or resected and primarily anastomosed (5 cases). Whilst in hospital, of those treated conservatively five died, and three from those treated surgically, four from those in which a colostomy was formed died and three from those in which a primary anastomosis was fashioned died. Of those that survived 11 from the conservative group had at least one recurrence, but none recurred following surgery. In conclusion, acute sigmoid volvulus affects an old and infirm population and carries a poor prognosis. Conservative management is initially preferable, but if emergency surgery is necessary a colostomy rather than primary anastomosis is indicated.