Unilateral pulmonary artery agenesis is a rare anomaly. It can be seen as either isolated or associated with other congenital heart diseases. It arises from the absence of development of ipsilateral sixth aortic arch. Since this disease can remain asymptomatic for a long period, the diagnosis may be delayed. In this article, we described a-7-year old patient with congenital left pulmonary atresia with the findings of echocardiography, thorax computerized tomography, and cardiac catheterization.