Abstract: Objective: To investigate the optimal methods of diagnosing and treating double primary lung cancer. Methods: The data from 32 patients with double primary lung cancer who underwent surgery in our department from 1995to 2005 were retrospectively reviewed. Results: There were 16 patients with synchronous tumor and 16 patients withmetachronous tumor. Among the patients with synchronous double primary lung cancer, 10 were treated with lobectomy,and 6 were treated with combination of lobectomy and partial resection. Of the patients with metachronous second primarylung cancer, only 3 patients were treated with partial resection, and the others were received lobectomy or lobe sleeve re-section. The 5-year survival was 62.9% in patients with metachronous primary lung cancer and 16.9% in patients withsynchronous primary lung cancer. The 5-year survival was 46.6% in patients with lobectomy and 25.0% in patients withcombination of lobectomy and partial resection. The perioperative mortality was 3.12%. Conclusion: Surgery is the majortherapy for double primary lung cancer. Lobectomy and lymph node dissection should be performed provided that the lungfunction is good enough.