Staged resection (group T) versus acute resection (group R) for curative purpose was compared in a randomized study of 121 patients presenting with signs of left-sided obstructive colorectal tumours during emergency surgery from 1978 to 1993. Patients with distant spread were excluded. Transversostomy was done in 58 and resection without immediate anastomosis in 56. Duration of emergency surgery was shorter, blood transfusions fever and wound infections less frequent in T compared to R, but postoperative mortality was similar (eight patients in each group). The diagnosis of tumour was wrong in 11 patients in T and six 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 six 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. In conclusion, no major advantage besides shorter hospital stay could be demonstrated by acute resection without simultaneous anastomosis compared to the traditional 3-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.