Our aim was to evaluate any impact of preoperative resting pressure upon postoperative physiological results in patients undergoing ileal pouch anal anastomosis. Ninety patients who had undergone manometric study before and I year after surgery were divided irate two groups determined by a preoperative mean resting pressure of >50 mm Hg or less than or equal to 50 nam Hg. There were significant differences between these two groups concerning preoperative maximum resting pressure (P < 0.001) and length of the high-pressure zone (P < 0.005). However, such; La trend was not seen postoperatively. There were no differences between these two groups relative to postoperative mean or maximum resting pressure maximum squeeze pressure, length oi high-pressure zone, sensory threshold, or capacity. The mean resting pressure decreased after pouch surgery in 82 Her cent of patients with a preoperative mean resting pressure of >50 mm Hg. Conversely, 83 per cent of patients with a preoperative mean resting pressure of less than or equal to 50 mm Mg experienced an increase in mean resting pressure after pouch surgery. Only 4 of 23 patients with a preoperative mean resting pressure of less than or equal to 50 nun Kg had decreased postoperative mean resting pressure, This latter finding has not been previously described, However, the mean resting pressure of those four patients more than fully recovered within 2 to 3 years after surgery, Although preoperative manometry may be useful to analyze data and to counsel patients, if should not be used to deny patients surgery. Moreover, this study has revealed that patients with lower resting pressures do not suffer a deleterious decrease in resting pressure but actually have improved postoperative mean resting pressure.