Real-time, cross-sectional echocardiograms of the pulmonary valve were recorded in 22 patients with valvular pulmonary stenosis (VPS) (14 mild, eight moderate or severe) and 25 normal subjects. Normally during systole the pulmonary leaflet echoes moved rapidly apart and in the fully opened position lay parallel and in close apposition to the margins of the pulmonary artery. In 20 of 22 patients with VPS in whom the pulmonary valve was recorded the systolic configuration of the leaflets, opening pattern of the leaflet echoes, and presence of presystolic doming served to differentiate the stenotic valve from normal. In contrast M-mode recordings of the pulmonary valve were possible in only 12 of these 22 cases (seven mild and five moderate or severe) and suggested VPS in only the five cases with moderate or severe stenosis. Cross-sectional echocardiography offers a direct, noninvasive method for visualizing the stenotic pulmonary valve and should be improvement over the indirect M-mode data.