Arrhythmogenic right ventricular dysplasia is characterized by fibrous and adipose replacement of the right ventricular myocardium and recurrent ventricular arrhythmias of left bundle branch block morphologic pattern. Sometimes the diagnosis is difficult because not all the clinical and instrumental findings are present and the separation between arrhythmogenic right ventricular dysplasia and other right ventricular cardiopathies is uncertain. In such cases the angiographic appearance of the right ventricle has been considered the "gold standard". To assess the diagnostic value of right ventricular morphology in identifying arrhythmogenic right ventricular dysplasia, we compared the angiographic findings of 8 patients with arrhythmogenic right ventricular dysplasia, 10 with biventricular dilated cardiomyopathy and 10 with Ebstein's anomaly. The following aspects were considered: deep fissuring of the anterior or inferior wall, outflow tract enlargement, contrast persistence in the right ventricle during the levophase, regional wall motion abnormalities including aneurysmal formations and tricuspid regurgitation. Aneurysmal formations of the right ventricle were found only in arrhythmogenic right ventricular dysplasia whereas the other angiographic findings were common to all the above mentioned diseases. Right ventricular angiography is an important adjunct to the clinical and instrumental diagnosis of arrhythmogenic right ventricular dysplasia, but most of its angiographic features are common to other diseases which cause right ventricular dilatation.