It is uncertain whether the dissection of the pulmonary ligament is necessary in patients who undergo an upper lobectomy. A questionnaire was sent to the directors of Thoracic Surgery in 102 hospitals, asking whether dissection of the pulmonary ligament is performed in such patients, and the complications associated with dissecting or preserving the ligament. Seventy-eight directors (76%) returned the questionnaire. The preservation of the ligament is the current practice in 54 hospitals (69%), while 13 hospitals (17%) occasionally dissect, 9 hospitals (11%) regularly dissect, and 2 hospitals (3%) half dissect the ligament. Thirty directors experienced complications which were thought to be associated with dissecting the ligament: bronchial stenosis (21 directors), atelectasis (8), and bronchial obstruction (4). Twenty-six directors described complications thought to be associated with preserving the ligament: the pooling of pleural effusion (19 directors), insufficient expansion of lung (18), atelectasis (8), and empyema (7). Preservation of the ligament may therefore be useful in preventing bronchial stenosis and obstruction, while its dissection may be useful to prevent the pooling of pleural effusion.