We attempted balloon dilatation of native coarctation of aorta in 11 consecutive neonates and infants (age range 28 days-12 months, mean 4.6 +/- 4 months, all males) presenting with congestive heart failure. The peak to peak aorto-aortic systolic pressure gradient fell from 60 +/- 21 mmHg to 13 +/- 7 mmHg (range 0-30 mmHg) (p < 0.001). The diameter of coarcted segment increased from 2.5 +/- 0.65 mm (range 2-3.4 mm) to 5.4 +/- 0.9 mm (range 4-6.4 mm) (p < 0.001). No patient required surgical intervention. The peak instantaneous aorto-aortic systolic Doppler pressure gradient at 17.5 +/- 8.8 months (range 2-21 months) did not show any significant change (mean 17.5 +/- 8.89 mmHg range 0-30 mmHg). All patients except one showed improvement in congestive heart failure. None developed restenosis. On the basis of this experience we recommend that balloon dilatation of native coarctation of aorta in infants in congestive heart failure is a safe and effective procedure.