Fabry's disease (angiokeratoma corporis diffusum universale) is a disorder of sphingolipid metabolism affecting predominantly male patients. Renal damage is usually the cause of death in the fourth or fifth decade. Renal transplantation represents a new approach to correction of uremia and perhaps even of the basic congenital metabolic anomaly. In this case the patient, a 57-year-old man, developed renal failure at the age of 45 and received a renal allograft at that age. The transplantation was followed by complete remission of uremia and concomitant symptoms, but later complicated by progressive cardiac failure, anginal chest pain and arrythmia. Necropsy findings showed persistent deposition of ceramide in the myocardium and especially in the conduction system. This was documented, for the first time to the author's knowledge, by electron microscopic investigations. Cardiac manifestations of Fabry's disease are discussed in relation to patients with renal transplants.