METHODS Four patients who previously underwent pneumonectomy for lung cancer, underwent a new contralateral resection for a metachronous cancer. Functional evaluation of these patients was not different from the standard one and included ECG, spirometry, blood gas analysis and a careful clinical evaluation. A femoro-femoral bypass was used in 2 patients to work on a collapsed lung, High Frequency Jet Ventilation was used in 1 while the last patient was hyperoxygenated and then ventilation was discontinued for the time required for the resections. RESULTS Each method was free of complications. Operative mortality was nil. Two patients are alive free of disease at 66 and 14 months, two died for metastatic disease at 4 (N2 paratracheal nodes) and 12 months. CONCLUSIONS Patients with a single lung should not be denied a further resection on contralateral lung. A routine evaluation of cardiopulmonary function may be sufficient but a more sophisticated evaluation including exercise oxygen consumption test, cardiac catheterization, lung perfusion scan, should be used when there is some doubt on the possibility of the patients to sustain the resection. Due to the high operative risk of this kind of patients mediastinoscopy should be performed even if preoperative CT scan of the chest shows minimally enlarged mediastinal nodes.