From July 1983 to December 1992, 145 patients with mitral valvular disease underwent open heart surgery at Chonbuk National University Hospital. Of these patients, 89 patients[61.4%] required mitral valve replacement. 56 patients [38.6 %] had mitral valve repair. There were 32 women and 24 men and the mean age was 34.3 years[range 6 years to 62 years].There were 23 cases of pure mitral stenosis, 19 cases of mitral regurgitation and 14 cases of mixedmitral valvular disease. The mean duration of symptom was 4.53 years and mean mitral valvularorifice diameter[in cases of pure stenosis and mixed mitral valvular lesion] was 0.96 cm. According to the NYHA classification, the distribution of patients preoperatively was as follows; class IIa, 15 patients; class lib, 17 patients; class III, 22 patients; class IV, 2 patients. Four patients[7%] had an embolic history preoperatively. 24 patients[ 43 %] were in atrial fibrillation. In cases of pure mitral stenosis, the technique used included open mitral commissurotomy[21atients], open mitral commissurotomy with mitral annuloplasty[2 patients]. In mixed mitral valvular disease, open mitral commissurotomy[ll patients] and open mitral commissurotomy with mitral annuloplasty[l patient] were performed. In cases of mitral regurgitation, mitral annuloplasty[5 patients], mitral valvuloplasty[6 patients], mitral annuloplasty with valvuloplasty [3 patients] and ring annuloplasty [5 patients] were performed.There was one perioperative death related to acute renal failure and sepsis. One late death was occurred related to heart failure after 10 months postoperatively. One patient required reoperation due to restenosis and no embolic episode was occured. After operation, 34 patients were in NYHA functional class I, 20 patients were in class IIa.