One hundred and thirty-four patients with acute sigmoid volvulus are analysed. When the diagnosis is made preoperatively, decompression per rectum is effective in 85 per cent of cases, and should be the initial treatment of choice unless gangrene of the bowel is suspected. In this situation emergency laparotomy should be performed and where gangrenous bowel is confirmed a Hartmann resection appears to be associated with a low mortality and least complications. When the sigmoid loop is found to be viable, it should still be resected. The merits and pitfalls of various procedures in this situation are discussed.