The increasing use and success of pelvic ileal reservoir surgery places an ever more demanding role onto the surgical pathologist. Close surgical and pathological cooperation is critical for preoperative patient selection, for intraoperative diagnostic confirmation and for postoperative follow up. The long term consequences of pouch construction are, as yet, unknown, but there is much evidence to substantiate the need for life-long surveillance by clinical, endoscopic and pathological means to maximise the benefits of the pelvic ileal reservoir to the patient. This paper reviews the pathological input into these aspects of pelvic ileal reservoir surgery together with a critical appraisal of the likely long term consequences of pelvic ileal reservoir construction.