A number of metabolic syndrome (MS) definitions exist, and one’s cardiovascular disease risk may depend on the definition used. The authors compared the association of subclinical atherosclerosis (coronary artery calcification [CAC] score >0] and inflammation (white blood cell [WBC] count greater than or equal to the highest quartile) with 3 definitions of MS (those of the National Cholesterol Education Program Adult Treatment Panel III [NCEP ATP III], the American Heart Association/National Heart, Lung and Blood Institute [AHA/NHLBI], and the International Diabetes Federation [IDF]) in 458 asymptomatic men (mean age, 46±7 years). MS was present in 28%, 29%, and 34% according to NCEP ATP III, AHA/NHLBI, and IDF criteria, respectively. CAC was observed in 40% and high WBC count in 24%. After adjustment for age, smoking, and low-density lipoprotein cholesterol, the odds ratios for CAC scores >0 with MS by NCEP ATP III, AHA/NHLBI, and IDF definitions were 1.67 (95% confidence interval [CI], 1.02–2.72), 1.67 (95% CI, 1.03–2.70), and 1.63 (95% CI, 1.03–2.57), respectively. The multivariate odds ratios for high WBC count with MS by NCEP ATP III, AHA/NHLBI, and IDF definitions were 1.69 (95% CI, 1.04–2.73), 1.84 (95% CI, 1.14–2.95), and 1.66 (95% CI, 1.05–2.62), respectively. MS is associated with increased subclinical atherosclerosis and inflammation irrespective of various definitions.