The aim of the study is to assess the influence of celecoxib on relapse-free survival in completely resected patients with poor prognosis indicated by metastatic involvement of intrapulmonary/hilar (pN1) or ipsilateral mediastinal (pN2) lymph nodes. Celecoxib, a selective oral COX-2 inhibitor, was found to exert significant anti-proliferative activity against a variety of tumor cell lines in vitro, including NSCLC. COX-2 is frequently up-regulated in NSCLC cell lines and archival tumor samples. Its high expression was also correlated with poor prognosis of the patients. A clinical trial addressing the role of celecoxib as adjuvant treatment in radically operated patients with high risk of relapse is warranted.