A case of antegrade balloon-valvuloplasty in an 34-day-old premature 1820 g baby with a critical aortic stenosis is reported. After transseptal puncture of the interatrial septum a loop was formed within the apex of the left ventricle. In order not to endanger the anterior leaflet of the mitral valve a maximum distance to the mitral valve was maintained. After two antegrade balloon-dilatations the pressure gradient over the stenotic aortic valve was reduced from 80 mmHg to 15 mmHg. No hemodynamic relevant aortic regurgitation occurred. Antegrade balloon-valvuloplasty in critical aortic stenosis represents an alternative to the retrograde technique. Severe laceration of the ileofemoral arteries, which has been reported in up to 45% of all retrograde procedures, is avoided in antegrade balloon-dilatation. Comparatively, the antegrade passage of the catheter through the stenotic aortic valve is easily performed. No dislocation of the balloon occurs during antegrade valvuloplasty. Through this procedure the aortic occlusion-time is reduced to a minimum. Besides protection of the arterial vessels, reduction of the aortic occlusion-time seems to be an important advantage of this technique when compared with the retrograde approach.