Foreign body in the air way occurs most frequently in children and can produce different symptoms and signs, which may be confused with other disease. On occasion, it can be not only followed by some pulmonal complications, but also it is often difficult to be removed. Therefore it can be serious and fatal. During the 7 years from 1967 to 1973 inclusive, 40 cases of air way obstruction due to foreign body were treated at Busan University Hospital. These cases were evaluated with regard to the particular clinical and roentgenographic features of air way obstruction due to foreign body and discussed some aspects of the treatment. 1) The incidence of sex is higher in male than in female, and children under 5 years old are prone to foreign body in air way. 2) The variety of foreign body is numerous, among which pointed metals and fish bone are most frequently found. 3) The larynx and trachea are the most favorable sites which foreign body is lodged. 4) The commonest clinical manifestations are cough, dyspnea and decreased air entry. 5) A negative roentgenographic examination does not exclude a foreign body. 6) Important complications due to foreign body are pneumonia, atelectasis and so forth. These seem to be trend to be produce by bean, fish bone and foreign body in valved form. 7) Removal of foreign body is performed more favorable by use of peroral endoscopy. However inferior endoscopy or general anesthesia can give us better way under some circumstances.