Two patients at our institution underwent single lung transplantation. The procedure and the patient's postoperative course were uncomplicated in each case. Pathological examination of each pneumonectomy specimen revealed a well-differentiated adenocarcinoma; both were less than 1 cm in size. The remainder of each lung showed no evidence of adenocarcinoma and all lymph nodes were negative. Work-ups for an occult malignancy before and after surgery were negative. This is believed to be the first report of a single lung transplant in a patient with a primary adenocarcinoma of the lung. The implications and management of these patients are discussed.