Arrhythmogenic right ventricular cardiomyopathy presents a rather frequent familial occurrence. In the present study the cases of two brothers (25 and 30 years old, respectively) presenting with the peculiar finding of early involvement of right atrium, are described. Both subjects were investigated because of recurrent complex arrhythmias, including supraventricular (sustained atrial flutter, atrial tachycardia) and ventricular tachyarrhythmias (very frequent premature beats, nonsustained ventricular tachycardia). The associated echo-angiographic aspects of the right atrium and right ventricle were those typically described in arrhythmogenic right ventricular cardiomyopathy. The familial occurrence of simultaneous right atrial and ventricular involvement, to the best of our knowledge not previously described, can likely be due to the similar phenotypic expression of the same genotype. The prognostic significance of atrial involvement in right ventricular arrhythmogenic dysplasia is still to be defined and the clinical follow-up of these two cases may contribute to it.