Ebstein's malformation of the tricuspid valve is a complex and heterogeneous disorder that has diverse hemodynamic and arrhythmic manifestations. Hemodynamic dysfunction is due to valvar regurgitation and decreased pulmonary blood flow, varying in severity from mild tricuspid insufficiency to severe dysplasia of the right ventricle without forward flow. Atrioventricular reentrant tachycardia and atrial tachyarrhythmias are commonly associated with Ebstein's malformation. Treatment ranges from conservative medical management to the ablation of pathways by catheterization to complex surgical repair or palliation. All patients with Ebstein's malformation should be followed on a regular basis by a cardiologist familiar with congenital heart disease. The frequency of evaluations should depend on the severity of the disease and the presence of arrhythmias. A specialist in electrophysiology should also follow those patients with complex arrhythmias.