Eleven patients with full thickness rectal prolapse underwent ambulatory fine wire electromyography (EMG) of the internal anal sphincter (IAS), external anal sphincter and puborectalis muscle, and anorectal manometry using a computerised system. Examinations were performed preoperatively and at 3 months following rectopexy. The median preoperative IAS EMG frequency was 0.21 Hz (range = 0.05-0.30) and the median preoperative resting anal pressure (RAP) was 13 cmH2O (range = 2-84 cmH2O). A significant improvement in the IAS EMG frequency (median = 0.31 Hz; 0.23-0.47 Hz; p < 0.02) and RAP (median = 30 cmH2O; 20-84 cmH2O; p < 0.01) was noted post-rectopexy but these parameters remained significantly different from a group of normal controls (median IAS EMG frequency = 0.48 Hz; 0.25-0.61 Hz; median RAP = 76 cmH2O; 22-120 cmH2O). We suggest that repair of the prolapse allows the IAS to recover by removing the cause of persistent recto-anal inhibition.