A series of 1428 standard pulmonary resections (pneumonectomy 30%, lobectomy 66%, segmentectomy 4%) performed over a 13-year period was reviewed with regard to haemorrhagic complications. The incidence of intra-operative vascular injuries was 5%. The pulmonary artery was damaged in 50 of these 73 injuries, the pulmonary vein in 21, and the superior vena cava and the subclavian vein in one case each. Two deaths were associated with the intra-operative bleeding. The vascular lesions could be repaired without extensive resection of pulmonary tissue in all but 3 of the other patients, in whom two, three and five pulmonary segments, respectively, had to be sacrificed. Postoperative bleeding necessitated emergency thoracotomy in 37 patients (2.6% of the series), and in 3 patients autopsy disclosed such haemorrhage. The cause of the bleeding in 12 cases was slipping or cutting through of ligatures applied to divided major vessels (pulmonary artery in 8 cases, pulmonary vein in 3 and azygos vein in 1 case). Systemic arterial haemorrhage occurred in 15 patients and diffuse bleeding in 12, while one patient had a coagulation disorder causing bleeding. Nine of the 40 patients died, 7 of the haemorrhage and 2 of bronchopleural fistula. The death rate was significantly higher in postoperative than in intra-operative bleeding. The study demonstrated that the widely used and recommended transfixion suture is not absolutely safe to prevent slipping of ligatures from divided major intrathoracic vessels. A purse-string suture has proved to be a safer alternative.