The primary objective of this study is to investigate incremental cost effectiveness of Nifedipine CR and Amlodipine in combination therapy with Valsartan for the treatment of essential hypertensive patients.

To investigate incremental cost effectiveness, primary variables are mean treatment cost and achievement rate to target blood pressure level at the end of double-blind treatment period.

Inclusion Criteria:

Untreated patients or patients with previous treatment by antihypertensive agents whose blood pressure at sitting position at the time of the entry (Visit 1) is:

• SBP>/=160mmHg or DBP>/=100mmHg for untreated patients (SBP Systolic blood pressure, DBP Diastolic blood pressure)
• SBP>/=150mmHg or DBP>/=95mmHg for patients with previous treatment by antihypertensive agents

Exclusion Criteria:

• Patients whose blood pressure on either day of Visit 1 or 2 is: SBP > 200mmHg or DBP > 120mmHg.
• Patients with secondary hypertension or hypertensive emergency such as malignant hypertension.
• Patients with a history of cardiovascular or cerebrovascular ischemic event (stroke, transient ischemic attack, myocardial infarction or unstable angina) within six months prior to the study.
• Patients with a history of intracranial or subarachnoid hemorrhage within six months prior to the study.
• Patients with uncontrolled diabetes (HbA1c >/=8%)
• Patients with bradycardia or tachycardia (<50 bpm, >/=100 bpm), arrhythmia such as atrioventricular block (second and third degree), sinoatrial block or atrial fibrillation.