Abstract: Objective To evaluate the relation of circadian blood pressure rhythm with vascular status in elderly patients with isolated systolic hypertension.Methods Ankle-brachial index (ABI),brachial-ankle pulse wave velocity (baPWV) and carotid intima-media thickness (IMT) were measured in 74 elderly patients with non-dipper hypertension (non-dipper group)、78 elderly patients with dipper hypertension ( dipper group),and 72 healthy controls ( control group).Results In comparison with the dipper group,baPWV and IMT of the non-dipper group were significantly increased [ baPWV (1801.61± 314.27) vs (1658.67±274.80) (cm/s)],P<0.01; IMT:(0.96 ±0.22) vs (0.87 +0.19) (mm),(P<0.05),while ABI of the non-dipper group was decreased (1.03 ±0.17 vs1.12 ±0.18,P<0.01).Identification rate was significantly different among 3 groups when baPWV >1400 cm/s (x2 =12.57,P <0.01) or ABI <0.9 ( x2 =9.74,P <0.01).The detection of carotid plaques was also significantly different ( x2 =16.49,P < 0.01).Conclusions These findings suggest that vascular damage could be found in elderly patients with isolated systolic hypertension,especially in those with non-dipper hypertension.ABI,baPWV and IMT measurement may be helpful for the assessment of vascular status.