Many etiological factors play a significant role in the development of tracheal stenosis ; too high tracheostomy, too small stoma and the treatment with respirator using cuffed tube and wound infection. Although the incidence has been reduced due to development of surgical techniques and antibiotics, the frequency of tracheal stenosis which produces symptoms after tracheostomy ranges from 1.5% to 10%. In the management of the stenosis, mild cases are treated by mechanical dilatation with silicon tube or stent combined steroid, or removed under mass the bronchoscopy. But in sever stenosis, transverse resection with subsequent end-to-end anastomosis has been used in recent years. During about 10 years, from 1967 to 1977, a total of 23 patients with tracheal stenosis have been treated in Severance Hospital, and we have obtained following conclusions by means of clinical analysis of 23 cases of tracheal stenosis. 1) The incidence of tracheal stenosis was 23 cases among 1514 cases of tracheostomy (1.5%) Under the age of 5, these are 12 cases(52.2%) and incidence of this age group was 7.9%. There is no definite difference in the sexual incidence. 2) The duration of tracheostomy state ranges from 4 days to 16 months, and majority (20 cases, 87.0%) were more than 30 days. 3) The primary diseases requiring tracheostomy were following ; Central nerve system lesion ; 11 cases, upper air way obstruction ; 10 cases, extrinsic respiratory failure ; 2 cases. 4) Tracheostomies without intubation were 14 cases (60.9%). 5) Predominant pathogenic organism from infected stoma were pseudomonas (5 cases) and staphylococci (4 cases). 6) The major site of stenosis was the region of the stoma (17 cases, 73.9%). 7) The methods of treatment applied to tracheal stenosis were following corking and respiratory training ; 4 cases, nasotracheal intubation ; 6 cases, silastic T-tube ; 5 cases, fenestration ; 4 cases, revision ; 2 cases, and transverse resection and end-to-end anastomosis ; 2 cases.