Anastomosis of the gastrointestinal tract has been made more secure by the use of the EEA (U. S. Surgical Corp.) stapler. The development of anastomotic strictures after stapling anastomosis is one of the major postoperative complications of this method. This study was done to compare the incidence of anastomotic stricture between stapling anastomosis and layer-to-layer handsewn anastomosis. Twelve dogs were divided into two groups. In each group, two colonic anastomoses were performed. Intestinal contents were not allowed to pass through one of the anastomotic sites created in an isolated segment of the colon, but were allowed to pass through the other site in the remaining colon. By the 28th postoperative day, anastomoses made with the EEA stapler, which had been excluded from contact with feces, had developed significantly more strictures when compared with the other anastomoses (p less than 0.05). The anastomotic strictures were membranous in nature when examined macroscopically and histologically.