Recent studies have demonstrated that antineoplastic activity of Cox-2 inhibitors may depend on targets other than Cox: among those, nuclear factor kappaB (NFkappaB) seems the most promising. Although preclinical studies have suggested that aspirin and Cox-2 inhibitors may influence the progression of lung cancer, the molecular mechanisms of these protective effects in this tumor type has not been fully elucidated. We investigated the effects of celecoxib and aspirin in the induction of apoptosis and in the ability to activate NFkappaB in three non-small cell lung cancer cell lines. Apoptosis was evaluated by FACS, caspase activation assay and expression of apoptosis-related genes by RT-PCR, while NFkappaB activation was assessed by immunofluorescence. No apoptotic response was observed after treatment with both high and low dose of celecoxib. Nevertheless, celecoxib at both concentrations induced a strong NFkappaB activation, with increased expression of NFkappaB-dependent genes, such as bcl-2, bcl-XL and survivin. Similarly, aspirin at both concentrations did not induce any apoptotic response, but activated NFkappaB in a dose-dependent manner. This study supports the hypothesis that NFkappaB activation is an important effect of NSAIDs in lung cancer, leading to apoptosis resistance. This effect of both aspirin and celecoxib may be considered undesirable in lung cancer chemoprevention.