Extracorporeal membrane oxygenator (ECMO) support was provided for a 19-year-old boy undergoing right lung transplantation. Perfusion was begun several hours prior to transplant, to correct profound hypercapnia. After the operation, ECMO was required because of inadequate gas exchange by the transplanted lung. Perfusion was continued for a total of 96 hours. During this time, the temporary malfunction of the transplanted lung owing to the reimplantation response reversed, and the patient was successfully removed from the oxygenator and subsequently weaned from the ventilator. He died on the eighteenth postoperative day of bronchial dehiscence. ECMO support appears to be a feasible means of supporting patients during lung transplantation and during the period of reversible lung malfunction that may occur in the early postoperative period.