Arrhythmogenic right ventricular dysplasia (ARVD) is a poorly understood and often underdiagnosed disorder of the right ventricle, characterized by replacement of myocardium by fibroadipose tissue, arrhythmic manifestations, and sudden death. The disease occurs in families and is inherited as an autosomal dominant trait. This report describes five cases of ARVD identified by autopsy. In three of the cases, sudden death occurred in the young (16-28 years old) during or shortly after exercise. In another case, a 46-year-old man with no relevant medical history was found dead in his bathroom. In the last case, a 57-year-old woman died from pulmonary thromboembolism. In none of the subjects had the disease been diagnosed or suspected before death. Only one (a 21-year-old man) had previous typical symptoms of the disease. Autopsy examination showed right ventricle dilation and, in four cases, cardiomegaly. The right ventricular myocardium of all hearts was almost replaced by adipose tissue and to a variable degree by fibrous tissue, while the left ventricle myocardium demonstrated no, or only scattered, fibro-fatty infiltration. Postmortem diagnosis of ARVD can be important in identifying possible affected family members in order to initiate treatment.