The purpose of this study is to determine if there is greater blood pressure reduction using ramipril or hydrochlorothiazide alone or ramipril and hydrochlorothiazide together.

Inclusion Criteria:

• Previously diagnosed, or newly diagnosed essential hypertension. Blood pressure must be within a minimum and maximum range prior to drug treatment.

Exclusion Criteria:

• Inability to discontinue all prior antihypertensive medications
• Heart failure
• History of stroke, myocardial infarction, or chest pain within 3 years, or an abnormal heart rhythm
• Liver or kidney disease
• Certain drugs used to treat other conditions like an enlarged prostate gland, or arthritis
• Allergy or reactions to certain medications used to treat high blood pressure

Other protocol-defined inclusion and exclusion criteria apply.