This is non-randomized phase 2 study to evaluate toxicity and efficacy of VA with concurrent chemoradiotherapy (CCRT) containing weekly vinorelbine and cisplatin in patients with locally advanced inoperable non-small-cell lung cancer (NSCLC).All patients will be planned for three-dimensional conformal RT (3-DCRT). Concurrent weekly vinorelbine and cisplatin and oral valproic acid (VA)will be started at the first day of RT. Follow up will be conducted every 3 months after completion of the study treatment. Toxicity will be assessed using CTCAE, based on clinical examination and laboratory tests during the study treatment and at follow up visits. Response to treatment will be evaluated using RECIST criteria. Overall and progression free survival (OS and PFS) will be estimated using the Kaplan-Meier method.