Transcatheter embolization therapy has assumed an important role in the management of patients with congenital heart disease. A variety of embolization materials, most commonly steel coils, is available to treat or palliate patients with aortopulmonary collateral vessels or surgical shunts, arteriovenous malformations, and anomalous venovenous connections (common after surgical intervention for the univentricular heart). At many centers, coil occlusion has recently become the treatment of choice for patients with a restrictive patent ductus arteriosus (PDA). This article describes the materials and techniques of embolization therapy, as well as the common indications encountered in the practice of pediatric interventional cardiology.