Purpose: Study of rheumatic mitral regurgitation by echocardiography. Finding the correlation between some clinical manifestations and results of echocardiography in rheumatic mitral regurgitation. Materials and method: 62 patients with rheumatic mitral regurgitation being treated with rheumatic prevent in level 2, at Pediatric department of Hue central hospital, from 4/2006 to 4/2011. Diagnostic was performed by echocardiography to evaluate the valvular lesions. Results: The single mitral regurgitation was highest rate (54.8 percent), Mitral regurgitation often occurred at moderate and severe level (79 percent). And the systolic pulmonary artery pressure often occurred at moderate and severe level (66.2 percent). There is a correlation between increased levels of pulmonary arterial pressure with systolic murmur intensity clinically, the level of mitral regurgitation on ultrasound. No correlation between the degree of heart failure with mitral regurgitation level on ultrasound. Conclusion: Echocardiography is the useful tool to evaluate the rheumatic valvular lesions.