Pulmonary artery branch stenosis is a not uncommon congenital lesion, noted in approximately 4% of children at the time of cardiac catheterization. Real-time 2-dimensional echocardiography was used to examine 10 patients with angiographically documented pulmonary branch stenosis. Five cases of pulmonary artery branch narrowing were identified by echocardiography without prior knowledge of angiographic findings. In 5 other patients whose angiographic results were known, the narrowings were identified in 4 of 5 cases. These results demonstrate the feasibility of evaluating pulmonary branch stenosis with the nonionizing, noninvasive method of 2-dimensional echocardiography. © 1982.