Rupture of the bronchus following endotracheal intubation with a double-lumen tube is extremely rare in all complications of endotracheal intubation. We experienced a case of left main bronchial rupture following endotracheal intubation. This 58-year old female patient was diagnosed of well-differentiated adenocarcinoma of right lower lobe, stage IIB, preoperatively. She was intubated with Robertshaw double-lumen tube(35 Fr.) for Rt. lower lobectomy. Intraoperatively, Lt. main bronchial rupture was suspected because of pneumomediastinum and ventilation insufficiency and immediately repaired with monofilament absorbable sutures(PDS) through left thoracotomy. Postoperative course was uneventful.