The value of chemotherapy in advanced non-small cell lung cancer (NSCLC) has been shown in combination chemotherapy with cisplatin, which yields only marginal survival benefits. Chemoradiotherapy with cisplatin improves the survival of patients who have unresectable, locally advanced NSCLC when compared with the treatment by radiation therapy alone. The 2- and 3-year survival rates are nearly doubled on average. Neoadjuvant chemotherapy is more effective than surgery alone for the treatment of stage IIIA NSCLC in the randomized phase III trials. It is suggested that neoadjuvant chemotherapy will be a standard therapy for stage IIIA NSCLC which is marginally resectable. There are many studies about radiation methods such as hyperfractionated radiation therapy and CHART, irradiated dose, and timing of radiation. There is a need to develop new, more active anti-cancer agents, and to find more effective regimens.