Mounier-Kuhn syndrome (MKS) is a disease characterized by dilation of the trachea and mainstem bronchi. Due to the risk of airway leakage, pulmonary aspiration, and tracheal damage, MKS can be fatal in patients undergoing tracheal intubation. Moreover, MKS may not be diagnosed preoperatively due to its rarity. In this case, a patient undergoing neurosurgery was incidentally diagnosed with MKS during general anesthesia. During anesthesia induction, difficulties in airway management led the anesthesiologist to suspect MKS. Airway leakage was resolved in this case using oropharyngeal gauze packing. Anesthesiologists should be aware of the possibility of MKS and appropriate management of the airways.