Five children aged 2 to 6 years with isolated pulmonary valve stenosis underwent treatment by percutaneous transluminal balloon valvuloplasty. A peak systolic gradient between right ventricle and pulmonary artery (delta RV/PA) was reduced from 60.4 +/- 18.7 mm Hg to 21.7 +/- 12.6 mm Hg and the right ventricular pressure fell from 76.2 +/- 20.7 mm Hg to 43.0 +/- 16.4 mm Hg. There were no complications. Percutaneous transluminal balloon valvuloplasty is a safe method to treat isolated pulmonary valve stenosis. It benefits many patients over a long term period and may provide definitive treatment in some patients.