Eight elderly patients (mean (SD) age 72.6 (8.5) years) with severe calcified stenosis of the aortic valve were considered for transluminal balloon dilatation in the Thoraxcenter between March and November 1986. In one patient the procedure could not be performed because of technical difficulties. Balloons of increasing diameter (13-25 mm) were successively passed retrogradely from the femoral artery and manually inflated with pressures of 400-600 kPa (4-6 atmospheres). Post-dilatation, there were significant changes in left ventricular pressures (from 237/21 to 204/13 mm Hg), mean systolic gradient (from 66 to 41 mm Hg, systolic aortic flow (from 172 to 202 ml/s, and aortic valve area (from 0.47 to 0.74 cm2); the cardiac index did not increase significantly (from 2.4 to 2.5 l/min/m2). One patient developed a pseudoaneurysm at the site of the femoral artery puncture that required surgical repair two months after the procedure; one patient experienced an acute left hemianopia during the procedure but had almost completely recovered at discharge. Five patients maintained a clinical improvement at a mean follow up time of 4.5 months after the procedure; two patients underwent aortic valve replacement, one because of minimal haemodynamic improvement after aortic balloon dilatation and persistence of severe dyspnoea and the other because of late recurrence of symptoms caused by restenosis after a successful procedure. Aortic balloon dilatation provides an alternative treatment for patients who are poor surgical candidates for cardiac or extracardiac reasons. At this stage the limited haemodynamic improvements suggest that the treatment can only be regarded as palliative, although proposed technical advances may achieve better immediate results in the future. Long term follow up is needed to evaluate the usefulness of this technique.