The aim of combined modality treatment of lung cancer is to improve control of both local and metastatic disease. Retrospective reviews of the combined RT and CT modality in limited-stage small cell lung cancer (SCLC) showed an improvement of median survival and long term survival compared with CT alone. Among reports of 7 prospective trials in which patients were randomized so as to receive CT alone or CT with chest irradiation, combined modality treatment significantly increased the CR rate in 3/3, and the overall survival was significantly prolonged in 3/7. Concurrently combined modality treatment has a modest survival benefit in limited stage SCLC. Our phase 2 study combining RT with cisplatin-containing CT showed better improvement of response and survival than CT alone in non-small cell lung cancer (NSCLC). Four reports of prospective randomized studies have been performed to determine whether combined RT and combination chemotherapy might be better than RT alone in limited-stage NSCLC. Two of these studies demonstrated a survival and response advantage for the combined modality treatment. However, this approach for NSCLC reported so far has been disappointing, because of relative lack of effectiveness of the present CT.