In this study it is intended to compare the blood pressure lowering effect of the combination of candesartan cilexetil (candesartan) 32 mg and hydrochlorothiazide (HCT) 25 mg and the combination of candesartan 32 mg and HCT 12.5 mg to that of candesartan 32 mg alone in patients whose blood pressure is not well controlled on candesartan 32 mg monotherapy. The Primary Objectives are to compare sitting BP lowering effect of candesartan/HCT 32/25 mg and candesartan/HCT 32/12.5 mg with that of candesartan 32 mg, respectively.