The incidence of large-intestinal anastomotic leaks remains unacceptably high. For this reason, we studied the resistance to dehiscence of a telescoping type of anastomosis and compared it with the conventional one-layer, two-layer, and stapled anastomoses in a canine model. These experiments demonstrated that the telescoping anastomosis provided a more resistant suture line during the early postoperative phase and did not cause encroachment of the lumen by the diaphragm, which was consistently produced when an inverting suture line was used. Three days postoperatively the mean bursting pressures of the one-layer, two-layer, and stapled anastomoses were 31±12, 120±46, and 52±21 mm Hg, respectively. The telescoping anastomosis had a mean bursting pressure of 210±44 mm Hg, which was significantly (P<0.01) higher than those of all the other anastomoses tested. However, seven and 14 days after opertion, there was no statistically significant difference among the bursting pressures of the various anastomoses. When the different types of anastomoses were examined histologically, it was found that there was considerably more suture-line inflammation, edema, micro-abscess formation, mucosal ulceration and pericolic inflammation of the fat in the one-layer, two-layer, and stapled anastomoses than in the telescoping anastomosis.