To investigate the impact of arterial properties on orthostatic blood pressure (BP) dysregulation in older hypertensives, orthostatic BP dysregulation, a common phenomenon in elderly hypertensives, is associated with target organ damage and falls. However, the mechanism of orthostatic BP dysregulation remains unclear. The pulse wave velocity (PWV), related arterial stiffness, and the augmentation index (AI), a measure of arterial wave reflection, were measured in 365 older hypertensives. We classified the study patients into an orthostatic hypertension (OHT) group with orthostatic increase of systolic BP (SBP) of > or = 220 mmHg (n = 27) and an orthostatic normotension (ONT) group with an orthostatic increase of SBP of < 20 mmHg and orthostatic SBP decrease of < 20 mmHg (n = 338). Orthostatic AI was significantly greater in the OHT group than in the ONT group (OHT: 6.5 +/- 12% vs. ONT: -5.6 +/- 12%, p < 0.001), while supine AI and supine and orthostatic pulse rate were comparable between the two groups. There was no significant difference in the PWV between the OHT and ONT groups. Orthostatic hypertension was affected by altered aortic properties and associated with augmented wave reflection of arterial pressure.