From August, 1986 to December, 1989, mitral valve replacement was performed in 93 patients. Of the valve implanted, 42 were Duromedics, 35 St. Jude Medical, 15 Carpenter-Edwards and 1 Ionescu-Shiley. The hospital mortality rate was 3.2%[3 patients] and the late mortality rate was 4.3% [4 patients]. The causes of hospital death were LV rupture in 1, renal failure in 1 and hypoxic brain damage in l. The causes of late death were congestive heart failure in 1 and sudden death in 3. Follow-up was done on 78 surviving patients; mean follow-up period was 29.22$pm$9.09 months. The actual survival rate was 91.8% at 4 years. We concluded, therefore, that good clinical results could be achieved with mitral valve replacement in short-term follow-up, and long-term follow-up is also necessary.