Arrhythmogenic right ventricular dysplasia (ARVD) is a disorder in which normal myocardium is replaced by fibrofatty tissue. This disorder usually involves the right ventricle, but the left ventricle and septum also may be affected. Although the exact prevalence of ARVD is unknown, it is thought to occur in six per 10,000 persons in certain populations. After hypertrophic heart disease, it is the number one cause of sudden cardiac death in young persons, especially athletes. Patients with ARVD are usually men younger than 35 years who complain of chest pain or rapid heart rate. In some cases, sudden cardiac death is the first presentation. The initial diagnosis of ARVD is based on the presence of major and minor criteria established in 1994. Further confirmation of the diagnosis includes noninvasive studies, such as echocardiography and magnetic resonance imaging of the heart, and invasive studies such as ventricular angiography and endomyocardial biopsy. Patients with ARVD are treated initially with antiarrhythmic agents with serious consideration for automatic implantable cardioverter-defibrillator placement. In patients with persistent symptomatic arrhythmias, radiofrequency ablation, ventriculotomy, or even cardiac transplant may be necessary.