While there are no published data on the feasibility and efficacy of combined gefitinib and radiation therapy in Chinese population who might be susceptible to gefitinib monotherapy, clinical studies have demonstrated that combining gefitinib with external beam radiation to 66-74Gy and concurrent weekly chemotherapy after induction chemotherapy were tolerated without excessive toxicity. In the present trail, we hope to build on our own experience of using combined gefitinib and thoracic radiation with 3D-CRT or intensity-modulated radiotherapy (IMRT) technique in a phase I setting for stage IIIb and selected stage IV NSCLC. We will follow this treatment (RT and gefitinib) with 60 days gefitinib at standard systemic doses.