Tracheobronchial rupture following tracheal intubation with double-lumen endobronchial tube (DLT) is a rare complication, but may result in a massive air leakage with resultant pneumothorax, mediastinal emphysema and extensive subcutaneous emphysema in the postoperative period. We report a case of sustained laceration of the posterior membranous part of the trachea possibly due to overinflation of the double-lumen endobronchial tube. A 76-year-old, 45 kg, female was scheduled for a repair of her bronchopleural fistula. Following induction of anesthesia, intubation was performed with Robertshaw's DLT, and a tracheal cuff was inflated with 6 ml of air, but the sound of an air leak was heard coming from the patient's mouth during controlled ventilation. A further 5 ml of air was added 1 ml at a time into the tracheal cuff but the air leak sound continued. At that point, the sound was considered to originate from the bronchopleural fistula rather than from lack of sufficient air. After a thorough deflation of the tracheal cuff, 6 ml of air was reinjected and the operation was resumed. A 4 cm split was unexpectedly noticed in the posterior wall of the trachea during the operation and was repaired without complication.