The diagnostic tools available for the evaluation of mitral stenosis are two-dimensional and Doppler echocardiography, which are able to identify morphologic and flow changes. Two-dimensional echocardiography can be used to assess the morphological appearance of the mitral valve apparatus, including its mobility and thickness and the presence of calcified leaflets and subvalvular fusion. Wilkins'score permits evaluation of each variable which, on the basis of its severity, is scored according to a point system ranging from 1 to 4. In patients with severe mitral stenosis, a low total score (< 8) and elastic symmetric commissures suggest valvuloplasty. A total score > 10 and the presence of more than mild mitral regurgitation or of calcification of both commissures suggest valvular replacement. The left atrial and ventricular chamber sizes and other associated valvular diseases can also be assessed at two-dimensional or Doppler echocardiography. The severity of obstruction can be assessed using two-dimensional and Doppler echocardiographic area (pressure half-time, proximal isovelocity surface area, continuity equation) and with the mean transmitral gradient measured using a continuous wave Doppler signal across the mitral valve. Valvuloplasty can also be performed in patients with a high score when surgery is contraindicated. During follow-up it is necessary to evaluate the area, the mean gradient, the right ventricular systolic pressure and the presence of a residual atrial septal defect and mitral regurgitation. Restenosis is diagnosed when the valve area decreases to 50% of that achieved during valvuloplasty or surgery.