During the first 31/2 years of the Stanford heart-lung transplant program, 23 transplants have been carried out in 22 patients with severe pulmonary vascular disease. Actuarial survival curves predict 1 and 2 year survival rates of 71% and 57%, respectively, for all patients. As a result of increasing experience, the early mortality of 26% has been reduced, with only one early death occurring in the last eight patients; prior cardiac surgery was a contributing factor in three of the six patients suffering early deaths. Two late deaths occurred in the series 14 and 15 months after operation. One patient died suddenly as a result of an acute myocardial infarct and the other patient died because of respiratory failure. At autopsy, both patients had severe proliferative coronary atherosclerosis with obliterative bronchiolitis affecting the lungs. An additional patient required a retransplant for obliterative bronchiolitis 37 months after the initial procedure, and he too was found to have severe coronary artery disease. Hemodynamics and left ventricular function were normal in patients studied 1 and 2 years after undergoing the transplantation procedure. Thus, the early mortality and morbidity of combined heart and lung transplantation has been significantly reduced, but the long-term complications, particularly graft atherosclerosis and obliterative bronchiolitis, are yet to be fully controlled.