A total of 149 patients who underwent cardiac valve replacement between January, 1964 and June, 1979 in our institution have been survived more than 10 years postoperatively. The prosthetic valves primary employed in this series were both mechanical valve such as Starr-Edwards, Smeloff-Cutter, Wada-Cutter, Lillehei-Kaster valves and biological valve such as Hancock valve. Of these, 69 patients (46%) implanted with Starr-Edwards or Wada-Cutter valve were not anticoagulated postoperatively, and 52 (53%) underwent reoperation mainly for valve-related complications or aggravated other valve lesions during the follow-up period. One hundred and thirteen patients were confirmed to be alive at the end of June, 1989, with the follow-up period of 10 to 25 years. Of these, 98 patients (87%) are in the NYHA I or II at the present time. Other twenty-two patients were dead and fourteen were lost to follow-up over 10 years after operation. Although cardiac valve replacement may improve the longevity and the quality of life, available prosthetic valves were not ideal both in material and design. The increased risk of thrombogenesis of mechanical valve and the limited durability of biological valve necessitated re-replacement in the long-term period. Therefore, in addition to selection of the appropriate valve prosthesis, and optimal prevention of valve-related complications, early diagnosis and treatment of these complications are important to improve the long-term results of cardiac valve replacement.