In 1933, Nissen performed the first ileoanal anastomosis. Since then, ileoanal anastomosis has enjoyed only periodic popularity because numerous postoperative problems, primarily as a result of infection and incontinence, plagued the procedure. In recent reports, however, better postoperative results have been detailed which stem not only from improved surgical technique and better selection of patients but also from increased understanding of the physiologic mechanisms by which fecal continence is achieved. At operation, meticulous hemostasis and asepsis, accurate en bloc mucosal dissection and effective drainage each contribute to good functional results and the minimization of complications. In addition, patients who manifest evidence of dysfunction of anal sphincters, who are elderly or obese or who have Crohn's disease should not be candidates for ileoanal anastomosis. Finally, if the anal sphincters are intact, reliable ileal reservoir function, achieved by passive dilation, balloon distention or surgical construction of a pouch, may be the most important determinate of excellent clinical results after ileoanal anastomosis.