A prespecified subgroup analysis of a 44-week open-label extension study is presented. The efficacy and safety of the combination of amlodipine (AML) olmesartan medoxomil (OM), with and without the addition of hydrochlorothiazide (HCTZ), were investigated in patients aged ≥65 and <65 years, Blacks and non-Blacks and patients with and without type 2 diabetes. After an 8-week double-blind, placebo-controlled portion of the study, patients initiated therapy on AML 5+OM 40 mg per day, were uptitrated stepwise to AML 10+OM 40 mg per day, with the addition of HCTZ 12.5 mg, and 25 mg if blood pressure (BP) goal was not achieved (<140/90 or <130/80 mm Hg for patients with diabetes). Endpoints included the change from baseline in mean seated systolic BP, mean seated diastolic BP and achievement of BP goal. BP decreased from baseline for all treatments in each prespecified subgroup. By the end of the study, BP goal was achieved in 61.0% of patients aged ≥65 years, 68.1% of patients aged <65 years, 63.3% of Blacks, 67.8% of non-Blacks, 26.9% of patients with diabetes and 72.9% of patients without diabetes. The combination of AML+OMH±CTZ was efficacious, safe and well tolerated by these subgroups. © 2010 Macmillan Publishers Limited. All rights reserved.