&NA;A conscutive series of 28 patients with acutely obstructing carcinomas of the left colon and rectum were encountered during the last three years. Two patients treated by loop colostomy only were excluded from the study. Fifteen patients received a one‐stage operation of immediate resection and primary anastomosis without proximal colostomy. The remaining 11 patients were treated by a conventional staged operation. The operative mortality and complications were similar in both groups. The duration of hospital stay in the former was half of that in the latter. Of nine patients treated by subtotal or total colectomy with primary anastomosis, the average number of bowel movements three months after surgery was 1.8 per day. Intraoperative colonic irrigation was performed in five patients of the one‐stage group and permitted a safe primary anastomosis. The immediate results of the one‐stage operation were surpisingly good. The authors propose it as the treatment of choice for the majority of patients with obstructing carcinomas of the left colon and rectum.