Pulmonary artery hypoplasia is a rare malformation of childhood that is usually associated with cardiac abnormalities. In the absence of these cardiac malformations it is discovered later when respiratory signs appear. It was a 56-year-old patient who had been referred for dyspnea with cough. The physical examination was normal. Chest X-ray, thoracic computed tomography (CT) scan and echocardiography suggested the diagnosis of hypoplasia of the left pulmonary artery without associated cardiac malformations. The early diagnosis of hypoplasia of the pulmonary artery allows the close follow-up of these patient and the planning of an adequate management.