During the past ten years, 145 patients (130 with ulcerative colitis and 15 with polyposis) have undergone colectomy and endorectal ileal pull-through operations at the UCLA Medical Center. The mean age of the patients at operation was 22.4 years (a range of seven to 56 years). All of the patients had a two stage operation with temporary ileostomy. Five had an S-shaped reservoir (SR), one patient had a J-shaped reservoir (JR), 12 patients had no reservoir (NR), 97 had a lateral reservoir with the reservoir constructed at the second operation (LR-2) and 30 had a lateral reservoir constructed at the first operation (LR-1). The most common complications were reservoir inflammation, obstruction of the reservoir outlet, stricture of the ileoanal anastomosis, superficial wound infection and sinus tracts extending upward between the rectal muscle cuff and the pull-through segment of ileum. Forty-four patients underwent reoperation for one or more of the complications. Reoperation was performed upon 60 per cent of the patients with SR, 36 per cent with LR-2, 10 per cent with LR-1 and 17 per cent with NR. Of the reoperations, 33 were performed upon the first 50 patients. Only 11 of the last 95 patients required a corrective operation. Of the last 95 patients, 97.5 per cent are currently functioning well. Important features of the operative technique include using a short rectal muscle cuff (5 centimeters or less), constructing a short reservoir (less than 15 centimeters) and having a short reservoir spout (less than 2 centimeters). Although a reservoir reduces fecal urgency and frequency in most instances, patients with obesity, anorectal muscle spasm, severe rectal disease and thick mesentery may be best treated with no reservoir. In our experience, the LR-1 procedure is technically easy to construct, has a low incidence of complications and is the preferred technique.