Percutaneous balloon valvuloplasty can be considered a therapeutic alternative to surgery for pulmonary valve stenosis. In this analysis, our results will be reported with respect to the various balloon sizes as related to the diameter of the valvular ring as well as differing balloon catheters and the presence of other anomalies in addition to pulmonary valve stenosis. Balloon valvuloplasty was carried out in 23 infants and children ranging in age from one month to eleven years and in two adults at the age of 22 and 50 years, respectively, with a systolic pressure gradient across the pulmonary valve of more than 50 mm Hg or, in the presence of pressure gradients between 40 and 50 mm Hg, in association with a right ventricular pressure of at least 60% of that of the systemic pressure. In all patients echocardiography was carried out prior to the procedure to rule out valve dysplasia and Doppler echocardiographic determination of the pressure gradient was performed before and after dilatation. The diameter of the valvular ring was measured echocardiographically as well as from the right ventriculogram and the size of the balloon chosen accordingly. After diagnostic catheterization, the balloon catheter was advanced to the pulmonary valve with a guidewire. Under fluoroscopy, the balloon was completely inflated then the contrast medium immediately withdrawn, a procedure of seven to 23 seconds with the single-balloon catheter and five to nine seconds with the trefoil catheter. At the first dilatation, the larger portion of the balloon was advanced to the main stem of the pulmonary artery and was placed proximally for subsequent dilatations.(ABSTRACT TRUNCATED AT 250 WORDS)