To compare the blood pressure lowering efficacy, safety and tolerability of a combination drug to a single drug taken once daily in patients with uncontrolled blood pressure following a 4-week filter on the single therapy product.

Inclusion Criteria:

• Male and female patients with mild to severe hypertension (SiDBP 90-120 mmHg)

Exclusion Criteria:

• Systolic BP > 200 mmHg
• Secondary or malignant hypertension
• Taking more than 2 antihypertensive medications
• Hypertension induced by oral contraceptives
• Hx of cerebral vascular accident within 6 months
• Hx of angina, myocardial infarction, PCI, CABG, or decompensated CHF within 6 months
• Clinically significant AV conduction disturbance or potentially life threatening ventricular arrhythmias, valvular disease, cardiomyopathy, unexplained syncope
• History of angioedema
• Sensitivity to AII receptor antagonists or HCTZ, nephrotic syndrome,single kidney function
• Pregnancy or lactation.