It is well known that Swyer-James syndrome(Idiopathic unilateral hyperlucent lung) is a peripheral form ofobstructive emphysema caused by a sequelae of severe unilateral bronchiolitis or pneumonia, showingradiographically unilateral radiolucency and diminished pulmonary vascularity. During the period from Jan. 1976through July 1976 three cases of Swyer-James syndrome were observed at the Capital Armed Forces General Hospital.The diagnosis was based on the simple chest P-A view, bronchography and lung scanning in 3 patients and pulmonaryangiography was additionally performed in only one patient. History of acute severe pulmonary illness in childhoodwas remembered by all of them. Radiological manifestations were also all classical. Therefore, these cases arepresented with brief review of the literatures.