The purpose of this study is to evaluate the antihypertensive efficacy and safety of Fimasartan/Hydrochlorothiazide combination 60/12.5mg~120/12.5mg in patients with essential hypertension who are not controlled by fimasartan 60mg.

Inclusion Criteria:

• Male and female outpatients 18 years of age and older
• Patients with antihypertensive agents at screening: DBP<110mmHg or Patients without antihypertensive agents at screening: DBP 90mmHg~120mmHg
• Subjects who agree to participate in this sudy and give written informed consent
• Subjects considered to understand the study, be cooperative, and able to be followed-up until the end of the study
• Patients with not controlled blood pressure at baseline visit, by fimasartan 60mg 4weeks treatment, DBP 90mmHg~109mmHg and SBP<180mmHg

Exclusion Criteria:

• The sitting DBP is more than 120mmHg or severe hypertensive patient with sitting systolic blood pressure over 200mmHg Patients with secondary hypertension
• Patients who are measured the mean difference of mean blood pressure under SiDBP 10mmHg or SiSBP 20mmHg at screening or baseline visit
• Patients with severe renal(Creatinine more 1.5 times than upper limit of normal), gastrointestinal, hematological or hepatic(AST, ALT more 2 twice more than upper limit of normal)disease etc. which might affect absorption, disposition, metabolism or excretion of the drug
• Patients with postural hypotension
• Patients with sever insulin dependent diabetes mellitus or uncontrolled diabetes mellitus(HbA1c>9%, regimen change of oral hypoglycemic agents within 12weeks, treated insulin before screening)
• Patients with a history of myocardial infarction, severe coronary artery disease or clinically significant heart failure or valvular defect in last 6 months
• Patients with consumptive disease, autoimmune disease, connective tissue disease
• Patients with a history of type B or C hepatitis(include carrier)
• Patients with HIV or hepatitis
• Patients with clinically significant laboratory abnormality
• Patients receiving any drugs known to affect blood pressure or medical treatments that can influence the blood pressure
• Patients with allergy or contraindication to any angiotensin II receptor antagonists
• Female of childbearing potential who does not undergo hysterectomy or is not post-menopausal
• Patients judged to have a history of alcohol or drug abuse by the investigator
• Patients participated other clinical trial 12 weeks before Screening - Patients judged to be inappropriate for this study by the investigator with other reasons