The fiberscope is no longer an experimental instrument, and it is a state-of-the-art technique for airway management in the operating room, recovery room, and intensive care unit. Changing the oral tube to a nasal one is often necessary if the trachea is to be intubated for a long period. A nasal tube is better tolerated by the patient, is easier to secure when the patient is moved, and is easier to attach to the respiratory care equipment. We describe three cases report changing the oral tube to a nasal one in neurosurgical pa- tient post operatively under flexible fiberoptic laryngoscope, while the interruption of venti- lation is minimized.