Since its introduction in 1984, percutaneous transvenous mitral balloon valvuloplasty (PTMV) has emerged as an effective technique in the treatment of selected patients with severe mitral stenosis. The most important factors determining the haemodynamic and clinical outcome after PTMV are the anatomic and pathological features of the mitral valve apparatus. In patients with pliable, non-calcified valves, immediate success rates of well over 90% are achieved. Short-term follow-up studies of such patients after PTMV demonstrate a low rate of valve restenosis, with the vast majority of patients remaining much improved clinically. Less favourable immediate and short-term results are observed in patients who have non-pliable, calcified valves. Major acute complications of PTMV include thromboembolic events and the production of severe mitral regurgitation. It appears that, as a result of increased operator experience, better patient selection and refinements in the technique of PTMV, the rates of these acute complications are now very low. Follow-up studies will be needed to assess the long-term efficacy of the procedure. The first publications on this field are encouraging.