The aim of this study was to evaluate the possible repair of large rectal wall defects using an open pedicle ileal graft as a mucosal patch. This experiment was carried out in 14 adult mongrel dogs. By excision of a portion of the antimesenteric wall comprising 50-70% of the circumference and measuring 5-6 cm in length, a suitable full thickness defect was created in the lower part of the rectum. A segment of the distal ileum was then isolated on a mesenteric pedicle and opened from its antimesenteric border. This was sutured over the defect in two layers. The animals were observed for a period of 15 days to 12 months. All the animals survived the operation apart from 1 dog that died of fecal peritonitis. Function of the rectum generally remained normal. Barium X-ray did not show any obstruction, shrinkage of the patch, lumen dilatation or extravasation. At the time of autopsy pedicles of ileal grafts appeared intact and pulsating. On gross examination there was no evidence of focal hemorrhage, ulceration or any cicatricial thickening of the grafts. Healing was good and the ileal mucosa retained its villi and general characteristics without any major inflammatory reactions. There was an increase in the number of goblet cells which returned to normal in 6 months.