A case of a perilymphatic fistula occurring while flying is reported. A 51-year-old man, suffering from nasal obstruction due to cold, noticed fullness and hearing loss in both ears when his airplane descended. He felt dizzy after landing. The return flight the next day aggravated the symptoms. He came to our clinic three days after the onset of hearing loss. Audiological examination revealed sensorineural hearing loss of 85dB in the right ear and 35dB in the left ear. After treatment with steroid and vitamine B12, hearing recovered in the left ear, but hearing impairment remained in the right ear. Twelve days after the onset, exploratory tympanotomy of the right ear revealed a rupture of the round window. It was closed with perichondrium and fat. The postoperative course was uneventful and the hearing improved to 44dB.