The aortas in 41 specimens of aortic atresia (ten with associated mitral atresia) were studied for the presence of coarctation of the aorta. The basic lesion, causing varying degrees of obstruction, was observed in 31 instances (75%), 24 minor, seven with major degrees of obstruction. In half, the aortic lesion lay proximal to the ductus, and in the majority of the remainder, opposite the ductus arteriosus. The location of lesion and degree of obstruction was essentially the same whether aortic atresia occurred alone or in association with mitral atresia. Angiography is a fairly reliable method of identifying coarctation associated with aortic atresia. An additional point of interest was that in aortic atresia alone there was strong dominance of the male sex, while this tendency was not observed when mitral atresia was associated with aortic atresia.