The authors report a case of left main bronchus rupture following endotracheal intubation with a Carlens double-lumen tube. The bronchus rupture occurred during a cure of gastro-oesophageal-reflux and resection of oesophageal diverticula through a left thoracotomy. The patient was a 65-year-old woman treated with corticosteroids for an Addison's disease. The weakness of the bronchial wall initiated by the steroid hormones was an important factor contributing to the perforation. There is also a higher risk of rupture during oesophageal surgery because of surgical dissection and stretch on the tracheobronchial airway. This case demonstrates that such a complication can occur without ventilatory failure. A rupture must be recognized and treated surgically very rapidly. Recommendations regarding the use of double-lumen endotracheal tubes are reviewed in order to decrease the occurrence of such a complication.