Background and aim of the study: The study aim was to define the long-term outcome of pulmonary balloon valvulotomy (PBV) in adult patients. Methods: PBV was performed in 87 patients (46 females, 41 males; mean age 23 +/- 9 years; range: 15-54 years) with congenital pulmonary valve stenosis WS). Intermediate follow up catheterization (mean 14.6 +/- 5.0; range: 6-24 months) was performed after PBV in 53 patients. Clinical and Doppler echocardiography examinations were carried out annually in 82 patients (mean 8.0 +/- 3.9; range: 2-15 years). Results: There were no immediate or late deaths. The mean catheter peak pulmonary gradient (PG) before and immediately after PBV, and at intermediate follow up was 105 +/- 39, 34 +/- 26 (p < 0.0001) and 17 +/- 14 (p < 0.0001) mmHg, respectively. The corresponding values for right ventricular (RV) pressure were 125 +/- 38, 59 +/- 21 (p < 0.0001) and 42 +/- 12 (p < 0.0001) mmHg, respectively. The infundibular gradients immediately after PBV and at intermediate follow up were 31 +/- 23 and 14 +/- 9 mmHg (p < 0.0001), whilst cardiac index improved from 2.68 +/- 0.73 to 3.1 +/- 0.4 l/min/m(2) (p < 0.05) at intermediate follow up. Doppler PG before PBV and at intermediate and long-term follow up were 91 +/- 33 (range 36-200) mmHg, 28 +/- 12 (range 10-60) mmHg (p < 0.0001) and 26 +/- 11 mmHg (p = 0.2), respectively. New pulmonary regurgitation (PR) was noted in 21 patients (25%) after PBV. Five patients (6%) with a suboptimal result (immediate valve gradient greater than or equal to 30 mmHg) developed restenosis and underwent repeat valvulotomy 6-12 months later using a larger balloon, and with satisfactory outcome. Moderate to severe tricuspid regurgitation (TR) in seven patients regressed after PBV. Conclusion: The long-term results of PBV in adults are excellent, with regression of concomitant, severe infundibular stenosis and/or severe TR. Hence, PBV should be considered as the treatment of choice for adult patients with PS.