A 74-year-old male, a case of lung cancer, was arranged for right lower lobe lobectomy. However, unexpected difficult intubation was noted after induction of anesthesia. After intubation with a 7.0# ETT using light wand, a double-lumen tube (DLT) was successfully placed using an airway exchange catheter (AEC) and surgery was performed smoothly. What should be considered in a patient with a difficult airway who needs one-lung ventilation (OLV), and the indications and current methods of OLV, are discussed. Also, the value, limitations and possible complications of this method are discussed.