Three men with Fabry's disease (angiokeratoma corporis diffusum universal ) are described. In the first patient, atrial fibrillation appeared, and a permanent cardiac pacemaker (VVI) was implanted. Sick sinus syndrome with complete atrioventricular block was occurred on the second patient. Transvenous pacemaker (DDD) implantation was performed for him. The last patient was younger brother of the second patient. He demonstrated complete atrio-ventricular block, so cardiac pace maker (VAT) was implanted. They showed a low value of granulocyte's alpha-galactosidase activity. During 1 to 4 year follow up period, they showed no trouble about pacemaking. Fabry's disease is an disorder of glycosphingolipid metabolism. This disorder is characterized by the accumulation of trihexosyl ceramide in many sites. Cardiac involvement and abnormal electrocardiographic manifestations are common in this disorder. Permanent cardiac pacemaker is necessary for severe bradycardia caused by this disorder.