OBJECTIVE: Mitral valve prolapse (MVP) is the most common cardiac valvular abnormality in industrialized countries. Its prevalence has been estimated to be between 2% to 4%. However, some studies found the prevalence of MVP less than 1% which is significantly lower than the prevalence reported in the Framingham Heart Study. The purpose of this study was to determine the prevalence, demographic, clinical and echocardiographic characteristics of MVP in a large population-based epidemiologic study.