A clinical analysis was performed on 48 cases with mitral stenosis who received open mitral commissurotomy from December 1983 to June 1991 at the Department of Thoracic & Cardiovascular Surgery, Chungnam National University Hospital. Fifteen patients were men and 33 were women. the mean age was 35.6 years with the range of 16 to 61 years. The distribution of preoperative NYHA Functional Classes was as follows; class II, 25 patients; class III, 20 patients; class IV, 3 patients. Three patients had cerebral emboli preoperatively, all of whom were in atrial fibrillation. The preoperative electrocardiographic studies revealed that 32 patients had sinus rhythms and 16 had atrial fibrillations. Twenty-six patients had open mitral commissurotomy alone and 22 patients had additional cardiac procedures. Intraoperatively, there were 6 cases of left atrial thrombosis. There was no perioperative death but early postoperative complications were found in 3 cases. The patients were followed up from 2 to 99 months[mean 33.7 months . There was one case of late unexplained sudden death. There was a case of late postoperative cerebral infarction, 5 cases of mitral restenosis and 3 cases of congestive heart failure and/or arrhythmia. Mitral valve replacements were required in 3 patients.But, it is evident that open mitral commissurotomy has many advantages beyond mitral valve replacement concerning the results of the mitral valve replacement underwent during the same period at the Department of Thoracic & Cardiovascular Surgery, Chungnam National University Hospital.