Objective: Clinical staging of non-small cell lung cancer helps to determine the extent of disease and separate patients with potentially resectable disease from those that are unresectable. Since, clinical staging is based on radiologic and bronchoscopic findings, overstaging or understaging may occur comparing to the final surgical-pathologic evaluation. We aimed to analyze preoperative and postoperative stagings in order to evaluate stage migrations and our surgical strategy for marginally resectable patients. Methods: We did a retrospective analysis of 180 patients with non-small cell lung cancer who underwent resectional surgery between 1994 and 2000. In all patients, a thoracic computerized tomography and bronchoscopy were performed to define clinical staging (cTNM). Results: In 86 patients (47.7%) clinical and surgical-pathologic staging concurred. When comparing T subsets alone, correct staging, overstaging and understaging occurred in 133 (73.9%), 28 (15.5%), 47 (26.1%) patients, respectively. Only 13 of 21 patients (61.9%) who were thought to have T4 tumor preoperatively were found to have pT4. Also six patients with cT2 and five patients with cT3 were subsequently found to have T4 disease according to pathology. Clinical staging overestimated the nodal staging in 35 patients (19.4%), while underestimated the lymph node involvement in 45 patients (25%). Conclusion: Construction of cTNM stage remains a crude evaluation, preoperative mediastinoscopy in every patient must be performed. Preoperative limited T4 disease is not to deny surgery to patients since a considerable number of patients with cT4 are to be understaged following surgery. (C) 2002 Elsevier Science B.V. All rights reserved.