Abstract： Objective To compare the clinical effect of valsartan/amlodipine combination or irbesartan/hydrochlorothiazide(HCTZ)combination in very elderly hypertensives.Methods After a 4-week placebo period,94 hypertensives,aged 75-89 years were random given valsartan 160 mg/amlodipine 5 mg or irbesartan 300 mg/HCTZ 12.5 mg for 24 weeks according to a rospective study.After 4 weeks,amlodipine or HCTZ was doubled in non-responders.Patients were checked every 4 weeks.At each visit,sitting,lying and standing blood pressure(BP),systolic BP(SBP)and diastolic BP(DBP)were measured.At the end of placebo period and treatment period,electrolytes and uric acid were evaluated.Results Blood pressure was significantly decreased in both treatment groups,however,there was no statistical significance between two groups.BP changes from lying to standing position were significantly greater in the irbosartan/HCTZ group(-17.2/-9.1 mmHg)than that in the valsartan/amlodipine group(-10.1/-1.9 mmHg,t=2.14,P＜0.05 for SBP and t=3.11,P＜0.01 for DBP vs.irbesartan/HCTZ).Potassium significantly decreased and uric acid significantly increased(-0.4 mmol/L,t = 2.33,P＜ 0.05 and+29.7μ mol/L,t =2.54,P＜0.05 vs.baseline,respectively)only in the irbesartan/HCTZ group.Conclusions Both combinations had similarly effective in reducing clinical BP in very elderly hypertensives.However,valsartan/amlodipine offered some advantage and less pronounced BP orthostatic changes and absence of metabolic adverse effects.