The Video Assisted Thoracic Surgery Study Group was formed to collect data on thoracoscopic procedures in an effort to define the role for this new technique. With more than 40 participating institutions, 1,820 cases have been collected through December 1992. Lung nodules and pleural effusions represent the most frequent indications, and wedge resection and operation in the pleural space were the most common procedures performed. Four hundred thirty-nine procedures (24%) were converted to a thoracotomy because of the need for more extensive resection (219), inability to find the pathology (65), too large a lesion or difficult location (62), adhesions (58), equipment failure (25), or bleeding (10). Prolonged air leak (> 5 days) was the most frequent complication. Patients undergoing video-assisted thoracic surgery and wedge resection had a mean hospital stay of 5.1 days; video-assisted thoracic surgical lobectomy was performed in 38 patients, who had a mean stay of 6.3 days. Air leaks were more prevalent in patients with poor pulmonary function (forced expiratory volume in 1 second < 1 L) and the elderly (> or = 75 years) after video-assisted thoracic surgical wedge resection. Video-assisted thoracic surgery appears safe and may be advantageous for some procedures. Further studies will be required to define its precise role in thoracic surgery.