A case of congenital aplasia of the left lung in a young Korean male is presented together with a review ofthe literatures. The patient was 25 years old man who had suffered from intermittent exertional dyspnea and leftchest discomfort for five months. until that time, he was healthy and he had no specific symptom or sign. Thediagnosis was confirmed by chest films, tomography, lung scanning, bronchography and pulmonary arteriography.