St. Jude Medical cardiac valve replacement was performed in 90 consecutive patients from Jan. 1984 to Dec. 1987. 54 had mitral, 12 had aortic and 24 had multiple valve replacement. Follow up extended for 1 to 47 months[mean 17.1 month] with a cumulative period of 1351 months. The overall actuarial survival rate at 4 years was 87.1% and overall hospital mortality was 6.7%. The linearlized incidence of thrombotic obstruction, thromboembolism, valve failure was 0.8% / pt. yr. each. The lower incidence of valve related mortality or morbidity was statistically significant. The performance of the St. Jude Medical mechanical valve was excellent compared to other substitute valves and has low incidence of thromboembolism or valve failure.