Staged resection (group T) versus acute resection (group R) for cure was compared in a randomized study of 121 patients presenting with signs of leftsided obstructive colorectal tumours during emergency surgery from 1978 to 1993. Patients with distant spread were excluded. Transverse colostomy was done in 58 and resection without immediate anastomosis in 56. Duration of emergency surgery was shorter, blood-transfusions less and wound infections less frequent in T compared to R, but postoperative mortality was similar (8 patients in each group). The diagnosis of tumour was wrong in 11 patients in T and 6 in R. The proportion of patients surviving the second stage curative resection in T without a permanent colostomy (32/35) was higher than after acute resection (36/50) in spite of 6 patients having anastomotic surgery (Coloshield) at the time of acute resection in R. Days spent in hospital were less in R. Overall recurrence rates and survival rates were similar in T and R. No major advantage besides shorter hospital stay could be demonstrated by acute resection without simultaneous anastomosis compared with the traditional three stage procedure, which on the other hand carried a much smaller risk of a permanent colostomy. The latter should therefore serve as a control in a prospective evaluation of emergency resection with simultaneous anastomosis.