Combined heart and lung transplantation was used to treat seven patients with end stage lung disease. All were severely disabled, and their disease carried a poor prognosis. Six patients were well four to 33 months after transplantation. One patient died after 44 days from a primary cytomegalovirus pneumonia transmitted from the donor. All the survivors had normal exercise tolerance and greatly improved lung function. It is concluded that heart and lung transplantation is a suitable treatment for selected patients with end stage chronic lung disease.