Balloon atrioseptostomy is a life-saving procedure palliating certain congenital heart defects like transposition of the great arteries, right or left atrioventricular valve atresia, hypoplastic left heart syndrome, and pulmonary hypertension. Occasionally the Rashkind balloon septostomy technique may be ineffective in creating an adequate interatrial communication. We performed balloon dilatation of a restricted atrial septal defect using a balloon angioplasty catheter in a three-month-old infant.