Over the past 30 years, interventional cardiology has developed as a distinct subspecialty, playing a major role in the management of infants with CHD. In the neonatal period, a wide variety of transcatheter interventions are performed routinely, either as palliation or therapy, as adjunct to surgery, or in place of surgical intervention. Among these are creation or enlargement of ASDs to allow atrial mixing; balloon valvotomy to treat congenital valvar stenoses; balloon angioplasty or stenting of stenotic vessels (pulmonary arteries, coarctation of aorta, or systemic or pulmonary veins) or postoperative anastomoses; closure of [figure: see text] unwanted vessels (congenital fistulae or collaterals); and other miscellaneous interventions. A wide variety of patients are candidates for these procedures, including those with transposition of the great arteries or other defects with transposition physiology, left atrial outlet obstruction and hypertension, severe valvar pulmonary or aortic stenosis, hypoplastic stenotic pulmonary arteries with severe symptomatology, severe coarctation of aorta and high surgical risks, large aortopulmonary collaterals or other hemodynamically significant unwanted vessels, acute thrombosis of certain surgical anastomoses, and many more. In experienced hands, these procedures are highly successful and safe, with a low morbidity and mortality (less than 1%).