We have previously demonstrated the technical feasibility of an en bloc double lung transplantation in acute canine experiments. We have now conducted survival experiments in cynomolgus monkeys. Profound hypothermia and circulatory arrest were used to avoid the need for cardiopulmonary bypass in these very small animals. Because of the complexities of this technique, few long-term survivals resulted, but these experiments did confirm excellent lung function and satisfactory tracheal healing. On the basis of these experiments, we have performed our first clinical double lung transplantation on a 42-year-old woman with end-stage emphysema caused by alpha 2-antitrypsin deficiency. The patient has returned to normal activities with excellent lung function.