A 56-year-old-male with malignant pleural mesothelioma of the left lung underwent pneumonectomy and pleurectomy. Fiberoptic bronchoscopy was not done preoperatively. Anesthesia was induced rapidly and a double-lumen endobronchial tube was inserted. When we checked the position of the tube with a fiberoptic bronchoscope, we found that the normal right upper lobe bronchus was absent and that the inflated tracheal cuff had obstructed the right upper lobe bronchus originating above the carina. Then we changed the double-lumen endobronchial tube to a endotracheal tube with the blocker. Thereafter, the surgery was completed safely and his postoperative course was uneventful. Routine bronchoscopy is essential just after intubation and before extubation of the endobronchial tube in safe airway management. How to use a fiberoptic bronchoscope to check the position of a double-lumen endobronchial tube is also discussed.