Decreased arterial elasticity, an independent risk factor for cardiovascular (C-V) disease, is associated with C-V risk factors in middle-aged and older individuals. However, information is limited in this regard in young adults. This aspect was examined in a community-based sample of 516 black and white subjects aged 25-38 years (71% white, 39% male). The common carotid artery elasticity was measured from M-mode ultrasonography as Peterson's elastic modulus (Ep) and relative wall thickness-adjusted Young's elastic modulus (YEM). Blacks and males had higher Ep (P < 0.05); males had higher YEM (P < 0.0001); and blacks had higher wall thickness (P < 0.01). For the entire sample adjusted for race and gender both Ep and YEM correlated significantly (P < 0.05-0.0001) with age, BMI, waist, systolic and diastolic blood pressures, heart rate, product of heart rate and pulse pressure, triglycerides, total cholesterol to HDL cholesterol ratio, insulin and glucose. In a multivariate regression model that included hemodynamic variables, systolic blood pressure, product of heart rate and pulse pressure, age, triglycerides, BMI, and male gender (for YEM only) were independent correlates of Ep (R2 = 0.38) and YEM (R2 = 0.25). When the hemodynamic variables were excluded from the model, age, triglycerides, BMI, black race (Ep only), male gender, parental history of hypertension, HDL cholesterol (inverse association), and insulin (marginal significance) remained independent correlates of Ep (R2 = 0.20) and YEM (R2 = 16). Both Ep and YEM increased (P for trend P < 0.0001) with increasing number of independent continuous risk factors (defined as values above or below the age, race, and gender-specific extreme quintiles) that were retained in the regression models. The observed increasing arterial stiffness (or decreased elasticity) with increasing number of risk factors related to insulin resistance syndrome in free-living, asymptomatic young adults has important implications for prevention.