This paper describes the mechanisms of action of ionizing radiations combined with antineoplastic drugs. Some relevant drugs for the combined modality treatments of locally advanced lung cancer are reported. The meta-analyses including randomized trials comparing single agent (radiotherapy or chemotherapy) versus combined chemotherapy and radiotherapy in patients with unresectable non small cell lung cancer and limited small cell lung cancer are then reviewed. The clinical outcome in relation to different schedules of chemoradiotherapy (sequential, alternating and concurrent) is also focussed.