We analyzed 39 patients who underwent a 2nd resection for recurrent (solitary pulmonary metastasis) or 2nd primary lung cancer. Based on the pathological findings, 18 patients were diagnosed as recurrent lung cancer, and 21 patients were diagnosed as 2nd primary lung cancer. Overall 5-year survival was 69.4%. There are no difference between recurrent group and 2nd primary group. It is difficult to distinguish preoperatively between recurrent lung cancer and 2nd primary lung cancer, so we must be consider the 2nd resection as a curative resection for "2nd primary lung cancer".