Abstract: The aim of this study is to evaluate the relation of symptoms to valve stenosis. The hemodynamic data have been evaluated at rest and after exercise using exercise stress echocardiography. We prospectively studied hemodynamic data in 15 consecutive patients with moderate MS who were in NYHA FC two or more. Treadmill exercise stress echocardiography (Bruce protocol) was done (GE Vingmed CFM 800).Mitral valve area (by planimetry and PHT method), mean TMVG, peak TMVG and PAP were measured in all the patients at rest and within 90 sec, after the termination of exercise. In 66.7% patients with moderate mitral stenosis the stenosis was hemodynamically significant regarding to increase in mean TMVG (2 times in comparison with rest or more than 15 mmHg) and PAP after exercise. Our results suggest that in patients with moderate mitral stenosis hemodynamic response to exercise has better correlation with the degree of valve stenosis severity and the occurrence of symptoms. In these patients exercise stress Doppler echocardiography is a noninvasive and reliable method to assess the mitral flow characteristics.