End-to-end implantation of a graft is the most commonly used procedure for vein implants in the venous system. In contrast to the growing literature on this method of venous grafting,1 no information is available on the end-to-side implants. Since in some clinical conditions it might be necessary to carry out a bypass procedure around veins involved by thrombosis or neoplastic invasions, its experimental investigation appeared desirable. The present study was therefore designed to evaluate the fate of such grafts and was carried out in two venous areas: the jugular and the inferior vena cava. Methods and Material Fifty-six adult mongrel dogs weighing 10 to 19 kg were used. The procedures were performed under intravenous anesthesia with pentobarbital (Nembutal) (12 mg/kg body weight). Fresh autogenous grafts were used in all experiments and secured from the right external jugular vien. A four-stay suture technique2 was always used for the end-to-side