During recent years, lung transplantations have been performed as lung transplantations or heart-lung transplantations in approximately 300 patients with terminal pulmonary or pulmonary vascular disease where other forms of treatment were considered hopeless. Two of the patients were Danish and operation was undertaken in England. One and three year's survival are now so good that this form of treatment need no longer be regarded as being of experimental nature. The indications and contraindications for operation are described and the postoperative immuno-suppressive therapy and complications are reviewed. Employing strict criteria in selection, the annual number of patients in Denmark is estimated to be approximately 50 and this is an adequate basis for a transplantation centre. At present, the procedure for selection of patients for operation is still vague and random in Denmark.