Objective　To evaluate the effect of radiotherapy（RT）combined with chemotherapy(C) for stage Ⅲ non-small-cell lung carcinoma (NSCLC) and to find a more effective way of giving them.Methods　From Jan. 1995 to Dec. 1997 , 60 patients with stage Ⅲ NSCLC were randomized into two groups . RT alone group(30 cases) was given conventional fractionated DT 60～70?Gy/6～7 W. The combined group(30 cases) received conventional fractionated radiotherapy plus chemotherapy (DDP,5-FU,VP-16 and IFO, given simulatneosly). In some patients,chemotherapy was also siven before,during and after RT for at least 2 courses. Results　CR rates of RT and combined groups were 20% and 43%, respectively . PD rate of the two groups were 10%and 7% . The 1-,2-and 3- year survival rates were 42.4%,15.7%,7.8% in the RT group and 68.1%,37.8%,18.9% in the combined group(P<0.05). The median survival periods were 8 months and 15 months though the combined group had more obvious side-effects than the RT group. Conclusions　Combined therapy is able to improve obviously the survival rate of stage Ⅲ NSCLC with the induction therapy very important. We expect a more effective combination is to have RT and C simultaneosly or alternately given.