Surgical treatment and combined chemotherapy of non-small cell lung cancers during the last 10 years were analyzed. Overall 5 year survival rate of non-small cell lung cancer was 37% and those in stages I, II, IIIA and IIIB were 59%, 33%, 21% and 12%, respectively. Poor outcome in IIIA cases depended strongly on surgical respectability, however, adenocarcinoma cases depended more on the T factor and squamous cell carcinoma depended more on the N factor. IIIA cases, even though resected curatively, showed 10-20% local recurrence, indicating the importance of further improvement of the surgical procedure. In the cases with absolutely non-curative resection tumor remained in mediastinal lymph nodes or organs adjacent to the mediastinum, indicating the necessity of extended combined resection including contralateral mediastinal lymph nodes or organs adjacent to the mediastinum for better results of surgical treatment. Preoperative chemotherapy for the suppression of local recurrence and distant metastasis was significant only in very limited circumstances.