Balloon mitral valvotomy (BMV) was performed in 315 patients with severe pulmonary arterial hypertension (PAH) defined as pulmonary artery mean pressure ≥50 mmHg (group I). Results were compared with other patients with mild/moderate PAH (group II). Group I patients were younger and more symptomatic. Mean pulmonary artery (PA) pressure (62.2 ± 10.6 versus 32.6 ± 8.2 mmHg), transmitral gradient (27.8 ± 6.5 versus 19.3 ± 5.8 mmHg) and pulmonary capillary wedge pressure (PCWP) (31.6 ± 6.1 versus 22.8 ± 6.2 mmHg) were significantly higher, and mitral valve area (MVA) (0.66 ± 0.2 versus 0.85 ± 0.2 cm2) was significantly lower in group I. After BMV, there was significant reduction in mean PA pressure (34.8 ± 11.2 versus 21.1 ± 8.4 mmHg), transmitral gradient (8.0 ± 3.9 versus 7.0 ± 3.2 mmHg) and PCWP (12.8 ± 5.8 versus 11.0 ± 5.1 mmHg) in both the groups, with a comparable increase in MVA (1.77 ± 0.4 versus 1.84 ± 0.4 cm2). Despite their poorer baseline hemodynamics, group I patients showed better improvement in all hemodynamic parameters. Clinical and echocardiographic follow up was available in 257 patients (mean 33 months). The mean PA systolic pressure derived from TR velocity in 161 patients was 39.0 ± 14.2 mmHg, compared with a post-BMV value of 55.0 ± 16.9 mmHg, showing a sustained fall at follow up. Thus, BMV is safe and effective in patients with mitral stenosis and severe PAH, and has sustained benefits that are maintained at long-term follow up.