Background : Although rheumatic mitral stenosis is still a prevalent and clinically significant valvular heart disease in Korea, the natural history of rheumatic mitral stenosis has not been clearly determined yet. The present study aimed to evaluate the clinical and echocardiographic changes in patients with rheumatic mitral stenosis according to different therapeutic modalities. Methods : A total of 91 patients (66 women; mean age, 50.9±12 years) with dominant rheumatic mitral stenosis and mitral valve area of less than 1.5 cm2 who were followed for more than 3 years (mean: 5.1 years) were included in this study. The subjects were divided into 3 groups according to the therapeutic modalities for mitral stenosis (A: medical therapy (n=31), B: percutaneous mitral valvuloplasty (n=30), C: mitral valve replacement (n=30)). Clinical and echocardiographic follow-up was performed before and immediately after therapeutic intervention such as percutaneous mitral valvuloplasty (PMV) and mitral valve replacement (MVR) and every year thereafter. Clinical symptoms and echocardiographic findings were compared between 3 groups. Results : The patients of group B consisted of less females and more younger (p=NS). Clinical symptom of dyspnea was more severe in group B and C initially (A: 1.8±0.8, B: 2.5±0.8, C: 2.9±0.7; A vs. B, A vs. C, p<0.05) but more improved in group B and C (A: 1.6±0.5, B: 1.3±1.0, C: 1.6±0.5; A vs B, A vs. C, p<0.05) during the follow-up. The prevalence of atrial fibrillation did not change significantly during follow-up. Mitral valve area decreased significantly in A group from 1.1±0.4 to 0.9±0.3 cm2 (p<0.05), but, no significant change was observed in group B and C. No significant changes were observed in the left ventricular end-diastolic, end-systolic dimensions, and ejection fraction during the follow-up period. No clinically significant aggravations of associated valvular