Two cases of congenital diverticulum of the right ventricle are presented. In each case, the diverticulum was demonstrated by angiocardiography (venous in one and selective in the other). In the single case with selective right ventriculograms, pulsation of paradoxical nature was evident in the diverticulum. Fibrosis of the wall of the diverticulum was present in this case. In the other case, the wall contained normal myocardial tissue. In this case, venous angiocardiography was not adequate to demonstrate pulsation. In both cases the clinical features were like those of tetralogy of Fallot and the anatomic features like those of ventricular septal defect and pulmonary stenosis. One case was typical anatomically for tetralogy of Fallot; the other was classified as double outlet right ventricle with pulmonary stenosis.