Transluminal balloon aortic valvuloplasty was performed in two term neonates, ages 6 and 7 days, with critical aortic stenosis. Transluminal balloon coarctation angioplasty was also performed in the second neonate. The neonates presented in congestive heart failure and underwent unsuccessful treatment with digoxin, furosemide, and careful fluid management before balloon dilatation. In the first patient, the gradient across the aortic valve was reduced from 75 mm Hg before balloon aortic valvuloplasty to 34 mm Hg after the procedure. The second neonate showed clinical improvement after both dilatation procedures. In both patients, follow-up clinical and Doppler echocardiography findings suggest persistent improvement 5 months after the procedure.