There has been a rapid increase in the prevalence of obesity, type 2 diabetes and metabolic syndrome(MetS) over the past two to three decades in most Asian countries. According to the Korean National Health and Nutrition Examination Survey(KNHANES), the prevalence of MetS significantly increased from 24.9% to 31.3% between 1998 and 2007. The clinical significance of MetS is based on the increased risk for the development of cardiovascular disease(CVD). We analyzed the 8-year follow-up data of 2,435 healthy subjects and found that MetS was associated with an increased risk of CVD in both men and women(OR: 1.98, 95% CI: 1.30-3.03 in men; OR: 4.04, 95% CI: 1.78-9.14 in women). MetS was significantly associated with the risk for future coronary heart disease(CHD) in men(OR: 3.68; 95% CI: 1.93-7.01) and stroke in women(OR: 3.96; 95% CI: 1.58- 9.94). We also analyzed the echocardiographic findings of 1,600 healthy subjects to evaluate the relationship between metabolic syndrome and left ventricular diastolic dysfunction(LVDD). The patients with MetS exhibited significant differences in parameters of cardiac structure and the LV diastolic function compared to that observed in the patients without MetS. MetS was associated with an increased risk of LVDD(OR: 1.67; 95% CI: 1.18-2.37). These results suggest that the presence of MetS is associated with an increased risk for the development of serious CVD and abnormal changes in the LV structure and diastolic function, even before the development of overt CVD.