An experimental model of heterotopic intrathoracic cardiac transplantation making possible an evaluation of graft viability and function has been studied. The technique requires only two anastomoses in the normothermic state without cardiopulmonary bypass. In this model, the ascending aorta of the recipient animal may be occluded completely, enabling an increasing preload on the graft. In case of adequate myocardial preservation of the cardiac graft, the aorta may be completely occluded and the recipient systemic circulation can be sustained by the graft. However, in case of inadequate graft myocardial function, or in case of size mismatch, the recipient heart alone contributes to the circulation. This technique appears quite useful because of its simplicity, the elimination of the need for extracorporeal circulation while allowing a functional evaluation following cardiac graft preservation.