Seven patients with Ebstein's anomaly were studied by two-dimensional echocardiography, with and without stop-action technique, and by standard echocardiography. Sagittal two-dimensional echocardiograms visualized a small functional right ventricle and a large atrialized right ventricle. These two parts of the chamber were separated by the anterior tricuspid leaflet and its chordae tendineae. The echocardiograms corresponded to the findings of the right ventriculogram. In horizontal two-dimensional echocardiograms a huge anterior tricuspid leaflet, atrialized right ventricle, and a displaced septal tricuspid leaflet, intervening between the functional right ventricle and the sinus portion of the functional right ventricle, were visualized. The origin of the septal tricuspid leaflet was clearly shown to be abnormal in five cases. The left ventricle was small with distinct clockwise rotation of the interventricular septum. Two-dimensional echocardiography provided information useful in evaluation of the functions of the right ventricle and the tricuspid valve and determination of what surgical procedure to follow.