Patients must have histologically-confirmed diagnosis of stage IIIB or IV NSCLC, with prior treatment with Erlotinib. In the phase I study the upper expected number of patients will be eighteen. In the phase II thirty two eligible patients will be included in the study. The enrollment period will be approximately 1.5 years. All patients will be treated with Erlotinib and Vorinostat regimen. Participating hospitals will be those of the Spanish Lung Cancer Group (SLCG).