Patients who develop a second primary lung cancer after pneumonectomy may benefit from an additional resection and should not be automatically excluded from surgical consideration. These patients should be carefully selected based on lung cancer stage and cardiopulmonary reserve. The most important initial differentiation is to distinguish a true second primary lung cancer from metastatic recurrent lung cancer. Only patients who have stage I disease are candidates for this type of extended resection. Wedge resection with negative margins is the preferred procedure for peripheral tumors. Central tumors are effectively treated with segmentectomy.