Denervation of the rectum during rectopexy has been suggested as a reason for postoperative constipation. Bowel symptoms and anorectal function have been examined in a prospective randomized study of rectopexy with (n = 14) or without (n = 12) division of the lateral ligaments. Incontinence improved in both groups of patients. Division of the lateral ligaments increased the number of patients with constipation (three before operation, ten after operation, P less than 0.01). Mean and canal pressures were higher after operation in all patients. Rectal electrical sensory threshold increased significantly in those in whom the ligaments had been divided (preoperative 27.6 mA versus postoperative 56.7 mA; P less than 0.01) but not in those in whom they were preserved (39.0 versus 34.9 mA; P greater than 0.05). Prolapse recurred in six patients who did not undergo division of the lateral ligaments, but in none of the group in whom the ligaments were divided.