Closed mitral commissurotomy for rheumatic mitral valve stenosis was used in many tens of thousands of patients with excellent immediate results and durability, many patients having survived more than 20 years without reoperations. Gradually, this procedure was displaced by the open commissurotomy which has the advantage of direct visualisation of all valve components with immediate assessment of the anatomical and functional result. Open commissurotomy is applicable even in moderately fibrosed and/or calcified valves and in the presence of intra-atrial thrombus. Its results are well established and have not yet been bettered by less invasive procedures, such as percutaneous balloon mitral commissurotomy.