Arrhythmogenic cardiomyopathy is relatively sporadic genetically-linked condition characterized by fibro-fatty replacement of myocardium, particularly that of the right ventricle. The clinical picture is dominated by arrhythmias, less frequent are the signs of heart failure. The diagnosis is facilitated by new diagnostic schema based on findings of following examinations: electrocardiography, echocardiography, Holter ECG monitoring, signal averaged ECG, endomyocardial biopsy, eventually some other methods. Results of this examinations are placed into the system of major and minor criteria. The most important goal of the therapy is sudden cardiac death prevention, pharmacological therapy has only debatable effect, and fundamental improvement of the prognosis is achieved by cardioverter-defibrillator implantation.