The aim of this study was to determine the association between homocysteine and arterial wall stiffness in a biracial (black and white) community-based cohort of asymptomatic young adults. That increased plasma homocysteine was adversely associated with atherothrombosis was well recognized. However, findings about the association of homocysteine and arterial wall stiffness, an indicator of vascular damage, were conflicting. Plasma homocysteine and other cardiovascular disease risk-factor variables were measured in 735 white and 294 black subjects aged 24 to 44 years enrolled in the Bogalusa Heart Study. Large-artery stiffness was assessed in terms of aorta-femoral pulse wave velocity (af-PWV) using echocardiography Doppler. Men versus women had higher fasting homocysteine (8.85 vs 7.32 micromol/L; p <0.01), and blacks versus whites had higher af-PWV (5.47 vs 5.24 m/s; p <0.01). In bivariate analyses, log-transformed homocysteine significantly correlated with af-PWV (p = 0.0004). In multivariate stepwise regression analyses, systolic blood pressure, age, heart rate, log-homocysteine, log-Homeostasis Model Assessment of Insulin Resistance, and smoking, in that order, were independently and positively associated with af-PWV. In conclusion, plasma homocysteine was an independent correlate of arterial stiffness in asymptomatic black and white young adults and may be a potential marker for cardiovascular disease risk in this age group.