Arrhythmogenic right ventricular dysplasia or cardiomyopathy (ARVD/C) is a pathologic condition where the right ventricle is partially or totally replaced by fatty and fibrous tissue. The electrocardiogram (ECG) has a central role for diagnosis since it comprises two major and two minor criteria in the diagnostic criteria published by the Task 1 Force, although it is not 100% necessary to make a final diagnosis, because around 10% of patients with ARVD/C present with a normal ECG. In this article, we review the 12-lead electrocardiographic findings of patients with ARVD/C. ECG criteria observed during depolarization [prolonged terminal activation duration, epsilon wave, partial right bundle branch block (RBBB) and advanced RBBB of peripheral origin with characteristic ECG patterns] and repolarization abnormalities, (negative T waves) are reviewed in detail. More common ventricular arrhythmias and risk of sudden death, and how to use the surface ECG to stratify the risk, are part of our final comments.