Background and Objectives: Recent studies have suggested that blood pressure variability (BPV) has a positive relation with cardiovascular events in patients with hypertension. However, correlation between BPV and surrogate markers for arteriosclerosis is not clear. The aim of this study was to evaluate the relation between BPV and severity of arteriosclerosis in patients with hypertension. Subjects and Methods: Sixty-four hypertensive subjects, who has never been treated, were enrolled (mean age 55짹12yrs, 40 males) in this study. In all patients, systolic BP, day time systolic standard deviation(SD; index of the corresponding variability) and night time systolic SD were measured with 24hour ambulatory BP monitoring (ABPM). We evaluated the correlation between BPV by ABPM and severity of arteriosclerosis measured by intima media thickness (IMT) and pulse wave velocity (PWV). The patients were divided into 2 groups according to their BP profiles, i.e., non-dipper and dipper group, morning surge (MS; sleep-through MS���37mmHg) and non-morning surge group. We compared IMT and PWV between each groups. Results: Day time BPV and night time BPV did not show significant correlation with PWV and IMT. There were no significant differences in non-dipper and dipper. However, PWV was closely related with morning surge. The PWV was significantly higher in the MS group than in the non-MS group (16.2짹3.05 vs 15.7짹4.75, p<0.001). Conclusion: These results suggest that 24hour ABPM variability for systolic BP was not associated with severity of arteriosclerosis in hypertensive patients. Only morning surge is related with increased aortic stiffness. As for conclusion, morning BP surge measuring seemed to be a valuable method for clinical evaluation of arteriosclerosis.