Videothoracoscopy, routinely performed as the initial step of an operation, opens interesting opportunities for both the operative staging and treatment of lung cancer. Videosurgical maneuvers ensure thorough exploration of the cavity, thus avoiding unnecessary exploratory thoracotomies, confirming resectability of the lesion by open or, in selected cases, by a direct video-assisted approach. We report our experience of 155 patients submitted to videothoracoscopic operative staging between October 1991 and January 1994. Videothoracoscopic operative staging showed unresectability in 13 patients (8.3%) due to preoperatively unexpected (10 patients) or suspected conditions (3 patients). The remaining 142 patients were divided by staging of the lesion and general conditions into three groups. Group A consisted of 13 elderly patients with small peripheral tumor who could not tolerate lobectomy and who underwent thoracoscopic wedge resection. Group B consisted of 63 patients with peripheral clinical T1 N0 or T2 N0 tumor. Fifty-two lobectomies and 4 pneumonectomies were carried out thoracoscopically. Seven conversions to thoracotomy were necessary due to technical problems. The postoperative course was uneventful in 51, 5 had prolonged air leakage, and a bronchial fistula developed in 1 because of positive-pressure postoperative ventilation. Group C consisted of 66 patients with stage II or IIIa neoplasm. Thoracotomy after thoracoscopy proved unresectability in 4, whereas 62 were submitted to a radical pulmonary resection. In the literature the incidence of exploratory thoracotomies for conditions missed by preoperative staging still remains high. After adoption of videothoracoscopic operative staging we reported a 2.6% exploratory thoracotomy rate.(ABSTRACT TRUNCATED AT 250 WORDS)