Sixty-three ears of 49 patients with serous otitis media were treated making use of butterfly ventilation tube in our 4 hospitals and 1 private office. The average time from intubation to extubation was 9 months and the longest case was 33 months. Main complications were infection and spontaneous extubation. The rate of hearing improvement after tympanostomy was more than 80% in all cases. The frequency of the most improvement was observed in 1kHz on the average. It was cleared that the butterfly ventilation tube was easy to use for the wide age patients and at any clinics. It was concluded that the butterfly ventilation tube was useful as a long-term ventilation tube.