Results about an echocardiographic study of 20 patients with Ebstein's anomaly diagnosed by cardiac catheterization and angiography, are referred. In 8 patients an echocardiogram and phonocardiogram were recorded and in five patients an echocontrast examination was performed. The echocardiographic features constantly recorded in Ebstein's anomaly are represented by anterior chamber dilatation, interventricular septum paradoxical movement, anterior tricuspid leaflet wide excursion, decreased diastolic closure rate and delayed closure of tricuspid valve compared to mitral valve. The reduced left ventricular dimension and frequent incidence of "hammock-like" shape of mitral valve during systole and reduced diastolic closure rate of anterior mitral leaflet are pointed out. Possible causes of anterior chamber dilatation, of interventricular septum paradoxical motion and delayed tricuspid closure are discussed. According to the previous study no echocardiographic pattern is surely diagnostic of the disease by itself; a delayed tricuspidal closure (more than 70 msec) when associated to an anterior tricuspid leaflet wide excursion and decreased E-F slope, is of particular value for diagnosis.