Cardiovascular disease is increased in US groups versus Japanese counterparts. Increased arterial stiffness is an important predictor of cardiovascular risk. Pulse wave velocity correlates well with arterial stiffness. Gender and ethnic differences in biracial US adolescent groups have been described. No data are available evaluating differences in arterial stiffness between US and Japanese subjects. Previously published data from an adolescent (12–17 years of age) Japanese cohort were used as an historical control and were compared to an adolescent cohort from the United States. The same simple noninvasive oscillometric technique was used in each cohort to measure brachial-ankle pulse wave velocity (baPWV) as an index of arterial stiffness. The US group was a cross-sectional, biracial (64% African American, 56% female) sample of 162 subjects. The Japanese group was a cross-sectional (48% female) sample of 820 Japanese subjects. All subjects in both cohorts were normotensive (BP < 95% for gender, height, and age) adolescents (12–17 years of age). Subjects were analyzed in four groups on the basis of gender and age (12–14 and 15–17 years of age). In both individual cohorts, the mean baPWV was higher in males versus females and the baPWV increased with age. The mean baPWV was higher in all US groups versus Japanese counterparts (p < 0.0001). The mean systolic and diastolic blood pressures were higher in all Japanese groups versus US counterparts (p < 0.005). Differences in arterial stiffness are present and detectable between normotensive US and Japanese adolescent subjects. Increased arterial stiffness among these adolescent groups correlates with known adult risk for cardiovascular events among the same ethnic and gender groups.