• Patients in whom carcinoma of the rectum develops at distances between 5 and 12.5 cm. from the margin of the external sphincter ani pose a difficult problem. The distance cannot be measured accurately, yet it decides whether a sphincter-preserving operation is possible. Seventy-five patients with lesions in this location were studied in the interval from October, 1945, to 1954, and additional data were available on 30 patients who underwent abdominoperineal resection for carcinoma in this location before October, 1945. In this study a comparison was made between two operations. Rectosigmoidectomy no. 1 consisted of abdominal dissection, resection, anastomosis, and cecostomy; rectosigmoidectomy no. 2 consisted of abdominal dissection, posterior resection, anatomosis, and a temporary colostomy of the transverse colon. The survival rates were found to be slightly better for the second operation than for the first, and the second operation, which saves the sphincter, gave rates similar to those for the abdominoperineal resection in which the entire area below the lesion, including the sphincter area, had been removed. This experience led to the conclusion that approximately 75% of patients with carcinoma between the 5-cm. and the 12.5-cm. levels can be given the advantages of a sphincter-saving operation without significantly decreasing their chances for a five-year survival.