The efficacy and complications of three different methods of percutaneous mitral valvuloplasty (PMV) were evaluated in 245 patients with mitral stenosis (MS). Eight six patients (35%) had severe MS defined in the mitral valve area (MVA) < 1.0 cm² (0.8 ± 0.2) and Echoscore ≥ 8(8.9 ± 1.1). The results including post MCA ≥ 1.5cm² and complications, i.e, increment of mitral regurgitation (MR) ≥ +1 and atrial septal defect (ASD) with Qp/Qs ≥ 1.5 were compared in overall and in severe MS groups. There was no statistically significant difference in size of MVA before and after PMV between overall patients group and severe mitral stenosis group (0.8 ± 0.1 vs 1.7 ± 0.4cm² in the double technique, 0.8 ± 0.2 vs 1.5 ± 0.3cm² in the Bifoil technique and 0.7 ± 0.2 vs 1.8 ± 0.3cm² in the Inoue technique. p: NS). However, a significantly larger number of patients in the severe MS group had better MVA with the double than the Bifoil technique [MVA ≥ 1.5cm²; 42 (72%) vs 6 (46%), p < 0.005] whereas higher complications were observed with the Bifoil than the Inoue technique (MR ≥ +1; 9 (69%) vs 4 (27%), ASD (Qp/Qs ≥ 1.5' 6 (46%) vs 2 (13%) p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)