We performed laryngotracheal plastic surgery by transplantation of autogenous costal cartilage graft in 9 cases of subglottic stenosis (2 with congenital type and 7 with acquired type). Of 9 cases, 3 cases had the lesion after long-term intubation, 2 cases after tracheotomy and 2 cases after laryngo-tracheo-bronchitis. Five cases aged one year and the remaining 4 cases 2 years, 3 years, 4 years and 6 years old, respectively. We could successfully decannulate in all the 9 cases after our plastic surgery. The period from surgical treatment to decannulation varied from 9 days to 6 months. However, 8 cases were decannulated in 2 months after surgery. Cotton et al (1978) did not use any stents in their treatment for subglottic stenosis, but we did in all of our cases. We preferred stents of the silicone Y-tube, and the recommendable duration of cannulation is 4 weeks.