Uhl's disease is a very rare congenital anomaly of the heart. Extreme dilatation of the right ventricle is accompanied by virtual absence of the right ventricular myocardium. We report on a 30-year-old woman with ventricular arrhythmias and atrial-septal defect where the diagnosis was made by echocardiography and confirmed by angiocardiography. Diagnostic and therapeutic possibilities are discussed.