Many of the pivotal early achievements in cardiac surgery were possible because of research using canine models. Specific advances attributed to canine experiments include the use of hypothermia, cardiopulmonary bypass, extra-cardiac surgery for congenital defects, heart transplantation, aortic and mitral valve replacement, and the surgical management of arrhythmias. In this historical review, we summarize specific experiments in each of these areas, and their subsequent clinical translation to humans. Our aim is to recognize these life-saving historical contributions that have been made by researchers and the sacrifices of canine patients.