Since its introduction as an alternative to surgical commissurotomy, percutaneous mitral valvuloplasty (PMV) has been performed in a large number of patients with mitral valve stenosis. PMV significantly improves valvular function, the final increase in mitral valve area being about 2 sq cm. The quality of the results obtained is principally related to the anatomy of the valve. The overall incidence of complications is low. The mortality rate ranges from 0.5 to 4 p. 100 in severe mitral stenosis. Left-to-right atrial shunting is detected by oximetry in 20 p. 100 of the cases, but it subsequently disappears in two thirds of the patients; late results are only known at medium term. When the initial result is satisfactory functional improvement is the rule and the incidence of restenosis is low. When the initial result is insufficient, or when mitral stenosis develops open heart surgery is usually necessary. The decision to perform PMV should only be made after exclusion of its contraindications: left atrial thrombosis, moderate to severe mitral stenosis. Because of the encouraging results obtained, PMV can be envisaged as first choice treatment of mitral stenosis with flexible cusps. In calcified mitral stenosis the standard treatment is mitral valve replacement, PMV being reserved to some particular cases.