Ileal pouch-anal anastomosis (IPAA) has become well established as the ideal surgical option for the majority of patients with chronic ulcerative colitis. Improvements and simplifications in operative technique over recent years mean that such patients need no longer live with the fear of a permanent ileostomy with its associated physical, sexual and sometimes psychological problems. Most patients who have undergone IPAA achieve a good quality of life. There are, however, a number of questions with regard to the ileal pouch that remain unanswered. The purpose of this review is to summarize the advantages and disadvantages of the various designs of pouch which have been described, to discuss the function of the normal pouch and manifestations of dysfunctional pouches.