Distal Surgical margin, required in the sphincter preserving operation for rectal cancer was studied histologically on the 78 resected specimens. The extramural cancer spread, examined by clearing method, was found in 20.5%, and was more frequent and expansive compared to intramural spread of cancer. No distal spread was found in cancer limited to the rectal wall. Length of the spread by 3 cm in lower rectal cancer and 4 cm in the upper rectal cancer. Postoperative anal function showed a good or fair in patients with internal sphincteric function preserved. Postoperative dysuria and male sexual disturbance showed a close relation to the pelvic nodes dissection. Ro-dissection was followed by 20% of dysuria, while RI and R 2 46.7%, R 3 1.8%.