Catheter therapy has gained an important role in the treatment of congenital heart disease. The cumulative experience with vascular and valvular balloon dilations has demonstrated low mortality and morbidity with short-term results similar to surgery. Currently, balloon dilation is an accepted treatment for valvular pulmonary stenosis, distal pulmonary artery stenosis, recurrent coarctation, rheumatic mitral stenosis, congenital valvular aortic stenosis, and intra-atrial baffle obstruction. Except for patients at high surgical risk, balloon dilation of native coarctation is considered investigational at most institutions but accepted at others. No conclusive evaluation is yet possible for dilation of bioprosthetic valves and membranous subaortic stenosis. Individual pulmonary veins appear undilatable. Various devices are available for closure of extra- and intracardiac communications. Transcatheter closure of aortopulmonary collaterals and arteriovenous malformations is now well established at some centers. In selected patients, therapeutic embolization of surgical shunts can replace surgery. Transcatheter closure of the patent ductus arteriosus has become routine at some centers. Nonsurgical closure of atrial and ventricular septal defects has entered clinical trials, and preliminary results appear very promising. Blade atrioseptostomy and foreign body retrieval are well established. Improvement of existing procedures and implementation of new concepts will consolidate the role of catheter therapy in congenital and acquired heart disease.