BACKGROUND: The augmentation index (AIx) is an index of wave reflection and a maker of systemic arterial stiffness. It also is associated with risk factors of cardiovascular disease. But Few study have reported the relationship between Aix and high sensitive C-reactive protein in patients with hypertension. OBJECTIVE: We identify that which factors influence on the abnormal augmentation index in hypertensive patients. . METHODS: The study is based on the subjects from Blood Pressure Behavior Study, a prospective registry of Korean Hypertension Network, which consist of the 12 cardiovascular center in Korea. All subjects were naïve hypertensive patients and the radial augmentation index was measured in all patients. To investigate the characteristics of the patients with abnormal augmentation index, the subjects were divided into tertiles on the level of baseline augmentation index. We measured epidemiologic, echocardiographic, hemodynamic and laboratory parameters for each hypertensive patients. RESULTS: We enrolled 656 naïve hypertensive patients. The mean age were 49+-11.4 year old and age was significant higher in the patients divided into the highest tertile of AIx. In the epidemiologic parameter, height (159.2+-6.8cm, p <0.001), weight (60.6+-9.5kg, p <0.001), body mass index (23.8+-2.9, p <0.001), waist circumference (81.3+-8.8cm, p <0.001) were significant lower and shorter in patients with the highest tertile of AIx. The social history of smoking and alcohol was significant frequent in highest tertile patients. In echocardiographic parameter, left ventricular mass and left ventricular wall thickness significantly higher and A���velocity also was higher. In the hemodynamic parameter, systolic blood pressure (office, ambulatory monitoring) were significant higher level in patients with the highest tertile of AIx. In the laboratory finding, the blood level of Hematocrit, creatinine was significantly lower and HDL-C was higher. In multivariate analysis, only body mass index (BMI, p=0.024, Exp(B) 35.97, 95% CI for Exp(B) 1.6-809.6) correlated independently, inversely with highest tertile AIx. CONCLUSIONS: These results suggest that the radial augmentation index is associated with traditional cardiovascular disease risk factor, but about weight and BMI the results showed inverse correlation in patients with hypertension.