Balloon valvuloplasty was used in the operating room on 7 patients to visually assess the valvular changes induced by inflation of a balloon catheter. All patients had typical pulmonary valve stenosis and an associated cardiac condition which necessitated surgery. Of 23 fused commissures present, 21 were successfully opened with a single balloon inflation. In 2 patients, damage to the leaflets was observed. In 1 patient there was partial detachment and in the other a small tear was noted at the margin of one leaflet. These intraoperative results may be similar to the results obtained with percutaneous balloon valvuloplasty.