A 32 year old man with no previous medical history suffered a sudden cardiac death. Post mortem examination revealed circumferential fibro-fatty infiltration of the left ventricular myocardium. Histological appearance was characteristic of arrhythmogenic right ventricular dysplasia but unusual for its localisation only to the left ventricle. As a result of this sudden cardiac death the family of the deceased was screened for cardiac disease. A brother of the index case was 36 years old and free of cardiac history and symptoms. Cardiac investigations revealed a functionally and electrically abnormal left ventricle with apparent sparing of the right ventricle. The brothers may have a left sided form of arrhythmogenic ventricular dysplasia and illustrate the importance of screening family members of young victims of sudden cardiac death.