Lobectomy by video-assisted thoracoscopic surgery (VATS) is gradually being performed more frequently because of advantages regarding pain and pulmonary function. Complications sometimes occur during or after VATS lobectomy. The purpose of this study was to analyze the incidence and the causes of the complications. From 1997 to 2003, 185 patients underwent VATS lobectomies. Selected diseases for this approach included primary lung cancer (n = 172), metastatic lung cancer (n = 7), benign lung tumors (n = 3) and lung sequestration (n = 3). The VATS approach was converted to open thoracotomy in 15 (8.1%) of 185 patients because of bleeding (n = 8), dense hilar adenopathy (DHA, n = 3), local extent of disease (n = 3) of intraoperative cardiac trouble (n = 1). Intraoperative complications involved injury to a blood vessel (n = 21), stapling failure (n = 15), lung injury (n = 7), nerve injury (n = 3), and others. Predictive factors for injury to pulmonary arteries was DHA (OR 37.0, p < 0.0001). Postoperative surgical death occurred in 2 patients due to pneumonia. Postoperative morbidity was 22.9%. A surgical operation without any good direct or thoracoscopic view or the use of a thoracoscopic tool without knowledge of the directions on its use should be avoided. The VATS approach should be replaced by open thoracotomy if there are DHA.