Heart and lung transplantation has only provided long-term survival for patients with end-stage cardiopulmonary disease. Many more patients of potential recipients cannot receive the transplantation because of a pause of satisfactory donors. One of its reason is difficulty in prolonged heart-lung preservation and this has imposed a significant barrier to donor procurement. Using Autoperfusion of heart and lung, six hours preservation was successfully achieved in six mongrel dogs and an adequate condition for preservation was evaluated. 1. Glucose metabolism, 2. Electrolytes, 3. Acid-base balance, 4. Pulmonary blood flow, 5. Temperature, 6. Ventilation were considered important factors for long hours preservation. Heart and lung preserved for six hours were transplanted in thirteen dogs in heterotopic and orthotopic models and their functions were evaluated two hours after transplantation. The cardiac function was well preserved and pathological changes in cardiac muscle were minimum. But lung preservation was not so stable. Levels of PaO2 were variable and pathological changes of the donor lungs such as pulmonary edema, emphysema, etc were observed. Further studies were needed for lung preservation.