Background -Calcific aortic valve disease is common in the elderly, is correlated with common cardiovascular risk factors, and is associated with increased cardiovascular event risk; however, whether metabolic syndrome is associated with an increased prevalence of aortic valve calcium(AVC) is not known. Methods and Results -The prevalence of AVC, as assessed by computed tomography, was compared in 6780 Multi-Ethnic Study of Atherosclerosis(MESA) participants with metabolic syndrome(n=1550; National Cholesterol Education Program’s Adult Treatment Panel III[ATP III] criteria), diabetes mellitus(n=1016), or neither condition(n=4024). The prevalence of AVC for those with neither condition, metabolic syndrome, or diabetes mellitus was, respectively, 8%, 12%, and 17%in women(P< 0.001) and 14%, 22%, and 24%in men(P< 0.001). Compared with those with neither condition, the adjusted relative risks for the presence of AVC were 1.45(95%CI 1.11 to 1.90) for metabolic syndrome and 2.12(95%CI 1.54 to 2.92) for diabetes mellitus in women and 1.70(95%CI 1.32 to 2.19) for metabolic syndrome and 1.73(95%CI 1.33 to 2.25) for diabetes mellitus in men. There was a graded, linear relationship between AVC prevalence and the number of metabolic syndrome components in both women and men(both P< 0.001). Similar results were obtained when the International Diabetes Federation metabolic syndrome definition was used. Conclusions -In the MESA cohort, the metabolic syndrome and diabetes mellitus are associated with increased risk of AVC, and AVC prevalence is increased with increasing number of metabolic syndrome components. Background -Calcific aortic valve disease is common in the elderly, is correlated with common cardiovascular risk factors, and is associated with common cardiovascular risk factors; and is associated with increased cardiovascular event risk; however, whether metabolic syndrome is associated with an increased prevalence of aortic valve calcium (AVC) is not known . Methods and Results -The prevalence of AVC, as assessed by computed tomography, was compared in 6780 Multi-Ethnic Study of Atherosclerosis (MESA) participants with metabolic syndrome (n = 1550; National Cholesterol Education Program’s Adult Treatment Panel III [ATP III] criteria, diabetes mellitus (n = 1016), or neither condition (n = 4024). The prevalence of AVC for those with neither condition, metabolic syndrome, or diabetes mellitus was, respectively, 8%, 12%, and 17% in compared with those with none condition, the adjusted relative risks for the presence of AVC were 1.45 (95% CI 1.11 to 1.90), women (P <0.001) and 14%, 22%, and 24% for metabolic syndrome and 2.12 (95% CI 1.54 to 2.92 for diabetes mellitus in women and 1.70 (95% CI 1.32 to 2.19) for metabolic syndrome and 1.73 (95% CI 1.33 to 2.25) for diabetes mellitus in men. There was a graded, linear relationship between AVC prevalence and the number of results of the International Diabetes Federation metabolic syndrome definition was used. Conclusions -In the MESA cohort, the metabolic syndrome and diabetes mellitus are associated with increased risk of AVC, and AVC prevalence is increased with increasing number of metabolic syndrome components.