One hundred eighty-eight patients undergoing abdominal colectomy with distal mucosal proctectomy and endorectal ileal pouch-anal anastomosis were reviewed to assess long-term functional results and to identify factors that might influence them. There was no postoperative mortality, but 10 patients (5.3%) required permanent ileostomy because of postoperative complications or the development of unsuspected Crohn's disease. Immediate postoperative complications, including pelvic sepsis, small bowel obstruction requiring surgery, anastomotic stricture, and ileostomy dysfunction, were observed in 11%, 9%, 14% and 9% of patients, respectively. No males were impotent but nine (9%) developed retrograde ejaculation. Pouchitis occurred in 8% of patients. Among 157 patients assessed at least 60 days after ileostomy closure (mean +/- SD, 375 +/- 216 days), all evacuated their neorectum spontaneously, and stool frequency was 6.0 +/- 2.6 daily and 1.2 +/- 1.3 nightly. While continence was generally good, 2.5% of patients during waking hours and 4.5% during sleep had occasional frank soilage. Moreover, seepage was noted in 25 and 47% of patients during daytime and nighttime, respectively. Both stool frequency and degree of continence improved with time. Patients less than 50 years of age and those with polyposis coli had fewer stools and better continence than those older than 50 or those with ulcerative colitis. It is concluded that ileal "J" pouch-anal anastomosis can be performed safely and will provide acceptable anorectal function without late deterioration.