Abstract Single-leaflet aortic valve homotransplantation was performed in 40 dogs with total circulatory arrest and with the aid of surface-induced deep hypothermia. Deep ether anesthesia, respiratory alkalosis, and low molecular weight dextran were considered essential in facilitating resuscitation and preventing ventricular fibrillation prior to intentional cardiac arrest. A single leaflet with narrow margins of adjacent aortic wall and myocardium was the most satisfactory preparation for insertion with 2 rows of sutures. There were no operative deaths. Seven early and 4 late deaths were the result of bacterial endocarditis or thromboemboli. Postoperative angiographic studies demonstrated valvular competence in 50 percent of the animals and moderate regurgitation in the remainder. This technique has proved to be a simple, safe, and satisfactory method for studying the ultimate fate of the homologous aortic valve.