Arrhythmogenic right ventricular dysplasia is an inherited fatal cardiomyopathy causing fat and connective tissue infiltration of right ventricle. In advanced disease, it may also involve left ventricle. Heart failure, arrhythmias and sudden death are main clinical components. Many different genetic mutations can cause this cardiomyopathy. All mutations lead to the formation of the disease are not yet defined. Basis of pathogenetic event is corruption of physical connection as well as the electrical conduction between cardiomyocytes due to these genetic reasons. Genetical inheritance is frequently autosomal dominant but incomplete. Because of the many different phenotypes, there may be great heterogenity of clinical manifestations in same family. Diagnostic criteria are renovated lately. Current cardiac imaging techniques for the diagnosis is gradually progressing. A combination of several tests should be used for diagnosis. Early and accurate diagnosis will save lives and improve the patient’s quality of life. In this paper, after mentioning the features and diagnosis of ARVD, differential diagnosis of ARVD from other diseases which may cause fatty infiltration of heart, arrhythmias and sudden death will be focused.