This chapter provides detail description of echocardiographic assessment of mitral valve disease. It contains echocardiography detailed, noninvasive information about the anatomy and etiology of valvular heart disease (both stenosis and regurgitation), the hemodynamic impact of the valvular lesion, and any associated complications. Thus, echocardiographic evaluation is now the instrumental tool in the management of patients with suspected or known valvular heart disease. The first part of the chapter “Echocardiographic assessment of mitral stenosis” in this chapter provides a concise overview of the echocardiographic evaluation of the patient with mitral stenosis (MS). The second part this chapter “Echocardiographic assessment of mitral regurgitation” deals with echocar­diographic assessment of mitral regurgitation (MR) because it forms an important component of other mitral valve (MV) diseases are covered here in some detail. 10 tables are included to highlight assessment of mitral valve anatomy according to the Wilkins score, severity of mitral stenosis (MS) based on PHT, definition of severity of mitral stenosis based on various parameters, classification of left atrial thrombus, assessment of mitral valve anatomy according to the Cormier score, proposed RT 3DE scoring system, role of 2DE in the evaluation of patients undergoing balloon mitral valvotomy, causes of mitral regurgitation, role of echocardiography in mitral regurgitation and echocardiographic assessment of mitral regurgitation (MR). 80 comprehensive and self-explanatory images are included in this chapter. And 84 references are given at the end of the chapter to facilitate further reading.