Patients with coarctation of the aorta can be treated either with surgery or with balloon angioplasty. So far, the last method has proved to be successful in children, but results of this treatment in (young) adults are virtually unknown. The aim of this study was to evaluate the immediate and mid-term follow-up results of balloon angioplasty of native coarctation in (mainly young) adults. Coarctation of the aorta was diagnosed by means of ultrasound or angiography, and defined as a stenosis with a pressure gradient greater than 20 mm Hg. The balloon angioplasty-procedure was carried out under complete anesthesia, and was considered to be successful, if the pressure gradient was reduced to less than 20 mm Hg. Nineteen consecutive adults (12 males, 7 females; aged 14-67 years, median 29) with native coarctation were treated from 1995-99. Mean pressure gradient decreased from 49.3+/- 20.8 to 4.8+/-8.2 mm Hg (P<0.0001). One patient showed a suboptimal result with a residual pressure gradient of 28 mm Hg. In one other patient a stent was placed on request of the referring physician. Follow-up was 100% complete and ranged from 3-47 months (mean 20.2+/- 12.9). At 1-year follow-up mean systolic blood pressure was reduced from 159.4+/-19.5 to 132.5+/-17.6 mm Hg (n = 18; P<0.0001), and mean ankle-arm pressure index improved from 0.73+/-0.09 to 0.96+/-0.05 (n = 18; P<0.0001). Anti-hypertensive medication could either be reduced or stopped in 7 patients (53.8%). With ultrasound or angiography or MRI, no patients had signs of aneurysm formation or worsening restenosis during follow-up. In adult patients with uncomplicated native coarctation of the aorta, balloon angioplasty (without stenting) would seem to be an excellent and safe alternative for surgery. In our hospital it has completely replaced surgical correction in such patients.