Background: Based on the revised AHA/ACC guidelines, it might be necessary to take into consideration the average life expectancy of Japanese people and revise the Japanese guidelines accordingly. Accordingly, we performed the present study to compare the long-term outcome in patients aged 65 years or older who underwent prosthetic valve replacement at our hospital using mechanical valves or biological valves.Methods: We have performed valve replacement in 416 patients aged 65 years or older (mechanical: 157; biological: 244).Results: There was no significant difference between the mechanical and biological valve for the actuarial survival rate. As for the valve-related complication free rate, in the mechanical valve group, the rates were significantly higher for all patients, aortic valve replacement (AVR) patients, and mitral valve replacement (MVR) patients.Conclusions: Following revision of the AHA/ACC guidelines for selection of prosthetic valves, it is necessary to investigate whether patients aged 60–70 represent the gray zone for selecting valves as in US and European guidelines, or whether a higher age is more appropriate in view of the longer average life expectancy in Japan. Accordingly, further evaluation of the long-term outcome for mechanical and biological valves in Japanese patients is needed to obtain evidence for preparation of original Japanese guidelines on prosthetic valve selection.