The objectives of this study were to determine the prevalence of, and factors associated with, postural hypotension (PH) in elderly treated hypertensive subjects, to examine the 24h BP profile in those subjects with and without PH and to determine the effects of antihypertensive treatment withdrawal on the prevalence and symptoms of PH. Eighty-six subjects (mean age +/- standard deviation 76 +/- 6 years) on antihypertensive drug therapy for > 6 months had three clinic BP measurements taken in supine and standing positions followed by 24h ambulatory BP monitoring. Forty-seven subjects underwent repeat BP measurement five weeks after withdrawal of antihypertensive medication and institution of standard nonpharmacological methods. Twenty-six (30%) of the 86 subjects exhibited PH (defined as SBP fall on standing > or = 20 mmHg) within three minutes of standing. Supine clinic and 24h SBP and DBP, age and presence of previous cardiovascular events were similar in the groups with and without PH. There was a significant correlation between the orthostatic BP fall for all subjects and day-night SBP difference (r = -0.30, P = 0.01) and urinary sodium:creatinine ratio (r = -0.33, P = 0.04). Multiple regression analysis revealed only the day-night SBP difference was a significant predictor of orthostatic BP change. In the PH group, 19 subjects had treatment withdrawn resulting in a reduction of 58% (P > 0.001) in those continuing to demonstrate PH. If indicated a trial of antihypertensive drug treatment withdrawal could reduce the risk of PH; the additional benefit of instituting nonpharmacological therapy in reducing BP and orthostatic hypotension warrants further assessment.