Background: Electron beam CT (EBCT)-determined calcium scores (CAC) are related to the severity of CAD. Metabolic syndrome X (central obesity, insulin resistance, low HDL-C, hypertension) is common in people with CAD, but its association with CAC is unknown.Methods: The relationship of CAC to the following parameters was assessed in 150 asymptomatic non-diabetic subjects: Serum lipid concentrations; subscapular and triceps skinfold thickness; waist/hip ratio; intra/extra abdominal fat; glucose and insulin in the two hour GTT. Correlations were analyzed for overall CAC and for cut off values of CAC > 0, CAC > 20 and CAC > 100.Results: CAC was negatively correlated with HDL-C (R = -0.19 for overall CAC and -0.22, -0.24 and -0.17 for the cut off points, p = 0.017, 0.009, 0.030 and 0.043), and positively with 2-hour insulin (R = 0.17, 0.21, 0.28 and 0.34, p = 0.036, 0.009, 0.001, and 0.0001), subscapular skinfold thickness (R = 0.21, 0.33, 0.20 and 0.25, p = 0.010, 0.0001, 0.015 and 0.002) waist/hip ratio (R = 0.28, 0.37, 0.32 and 0.35, p = 0.001, 0.0002, 0.0003 and 0.0002) and intra abdominal fat (R = 0.25, 0.39, 0.33 and 0.37, p = 0.004, 0.0001, 0.0003 and 0.0002). There were no significant correlations with LDL-C, Triglycerides, 2-hour glucose, or triceps skinfolds thickness.Conclusions: CAC scores correlate with characteristics of syndrome X but not with LDL-C, overall adiposity, or TG. EBCT is a unique tool for studying the epidemiology of pre-clinical CAD and may distinguish between those risk factors associated with development of the calcified atherosclerotic plaque and those associated with the acute coronary syndrome.