The purpose of this report is to review the role of echocardiography in the selection of patients for percutaneous mitral commissurotomy (PMC). Echocardiography has become the standard for the assessment of the severity of mitral stenosis and of its consequences. PMC is usually performed only in patients with a valve area of < 1.5 cm(2), whereas pulmonary hypertension or spontaneous echo contrast in the left atrium may lead to intervention in patients with few symptoms. The next step of the echocardiographic evaluation is to eliminate contraindications: left atrial thrombosis (by the systematic performance of a transesophageal examination before PMC), mitral regurgitation >/= 2/4, severe aortic valve disease, mixed tricuspid valve disease, and massive or bicommissural calcification. Finally, echocardiography allows the classification of patients into different anatomic groups for prognostic consideration. There is controversy regarding the best echo score system in the prediction of the results of PMC. Scores using a global evaluation of the valve anatomy are the most widely used, whereas more recently, scores taking into account the uneven distribution of the disease have had promising preliminary results. Overall, echo scores are useful criteria for selecting candidates for PMC, but they should be considered together with the other clinical and procedural variables. Thus, echocardiography has an important role in the selection of patients for PMC, as well as for the guidance of the procedure, the evaluation of the results, and surveillance.