Percutaneous mitral ballon valvuloplasty(PMV) is an effective nonsurgical procedure for patients with mitral stenosis. PMV was performed in 13 patients(mean age, 41 years) with mitral stenosis. All patients underwent echophonocardiography(Echophono) before and after PMV. Two dilatation balloons were used in which the diameters approximately equaled the mitral valve annulus diameter as determined. After PMV, the mean mitral valve pressure gradient decreased(22.3±1.89mmHg to 5.2±2.6mmHg), the mean left atrial pressure decreased(21.3±5.1mmHg to 9.0±4.5mmHg) and the mitral valve area increased from 0.8±0.3cm2 to 1.7±0.6cm2. The Echophono data are correlated with clinical and hemodynamic changes produced by PMV. PMV resulted in echophono changes consistent with decresed severity of mitral stenosis ; shortening of Q-S1, from 88±14 to 73±11 mses(p<0.01) and (Q-S1)-(S2-OS), from 0.9±1.7 to -2.1±1.6(p<0.001) ; prolongation of S2-OS from 80±15 to 103±14 msec(p<0.001) and increase of EF slope from 14.7±5.4 to 26.7±8.1 mm/sec(p<0.001).