The safety and efficacy of an amlodipine/olmesartan medoxomil (OM)-based titration regimen was assessed in patients with type 2 diabetes mellitus and hypertension. After a 2- to 3-week placebo run-in period, 207 patients received amlodipine 5 mg and were uptitrated to amlodipine/OM 5/20, 5/40, and 10/40 mg and then amlodipine/OM 10/40 mg plus hydrochlorothiazide 12.5 and 25 mg in a step-wise manner at 3-week intervals if the seated blood pressure (BP) remained ≥120/70 mm Hg. The primary end point was the change from baseline in the mean 24-hour ambulatory systolic BP after 12 weeks of treatment. The baseline mean ± SD seated cuff systolic/diastolic BP was 158.8 ± 13.1/89.1 ± 10.1 mm Hg and the mean ± SD 24-hour ambulatory systolic/diastolic BP was 144.4 ± 11.7/81.6 ± 9.8 mm Hg. At week 12, the change from baseline in the mean ± SEM 24-hour ambulatory systolic/diastolic BP was −19.9 ± 0.8/−11.2 ± 0.5 mm Hg (p <0.0001 vs baseline), and 70% of patients had achieved a 24-hour ambulatory BP target of <130/80 mm Hg. At the end of 18 weeks of active treatment in patients uptitrated to amlodipine/OM 10/40 mg plus hydrochlorothiazide 25 mg, the change from baseline in the mean ± SEM seated BP was −28.0 ± 1.5/−13.7 ± 1.0 mm Hg (p <0.0001 vs baseline), with 62% of patients reaching the guideline-recommended seated BP goal of <130/80 mm Hg. Drug-related treatment-emergent adverse events occurred in 19.3% of patients. The most frequent events were peripheral edema (6%), dizziness (3%), and hypotension (2%). In conclusion, this amlodipine/OM-based titration regimen was well tolerated and effectively lowered BP throughout the 24-hour dosing interval in patients with hypertension and type 2 diabetes.