&NA;Since November 1980, 180 patients underwent abdominal colectomy, rectal mucosectomy, ileoanal reservoir construction, and ileoanal anastomosis at the authors' institutions. One hundred twenty‐nine patients had restoration of intestinal continuity before the end of 1986. One hundred fourteen of these patients (88 percent) were available for follow‐up at a mean length of time of 5.0 years from ileostomy closure (range, 16 to 88 months). The mean number of pouch evacuations was 5.4±2.5 during the day (range, 1 to 12) and 1.5±1.0 at night (range, 0 to 6). Ninety‐one percent of patients reported perfect or almost perfect daytime continence, and 74 percent found this true at night. Sixty‐three percent of patients believed their pouch function continued to improve over many years. Ninety‐five percent of patients questioned would choose an ileoanal reservoir again instead of a permanent ileostomy. This long‐term assessment of the function of the ileoanal reservoir confirms that it is a viable, although not perfect, option in the management of ulcerative colitis and familial adenomatous polyposis.