Inclusion criteria:

1. Ability to provide written informed consent in accordance with Good Clinical Practice and local legislation;
2. Age 18 years or older;
3. Patients with grade 2 or grade 3 hypertension as defined SBP>=160 mmHg and DBP>=100 mmHg at randomization
4. Ability to stop any current antihypertensive therapy without unacceptable risk to the patient (Investigator's discretion)

Exclusion criteria:

1. Pre-menopausal women (last menstruation <=1 year prior to signing informed consent) who: a) are not surgically sterile; or b) are nursing, or c) are pregnant, or d) are of childbearing potential and are NOT practicing acceptable methods of birth control, or do NOT plan to continue practicing an acceptable method throughout the trial. The only acceptable methods of birth control are: Intra-Uterine Device (IUD), Oral contraceptives, Implantable or injectable contraceptives, Estrogen patch Hormonal birth control should have been in use for at least three months before the study and continue at least until the next menstrual period after completing the study.
2. Night shift workers who routinely sleep during the daytime and whose work hours include midnight to 4:00 a.m.
3. Known or suspected secondary hypertension (e.g., renal artery stenosis orphaeochromocytoma)
4. Mean in-clinic seated cuff SBP>= 200 mmHg and/or DBP >=120 mmHg
5. Renal dysfunction as defined by the following laboratory parameters: Serum creatinine >3.0 mg/dL (or >265 umol/L) and/or known creatinine clearance of <30 ml/min and/or clinical markers of severe renal impairment.
6. Bilateral renal artery stenosis, renal artery stenosis in a solitary kidney, post-renal transplant patients or patients with only one kidney
7. Clinically relevant hypokalemia or hyperkalemia (i.e., <3.5 mmol/L or >5.5 mmol/L, may be rechecked for suspected error in result)
8. Uncorrected sodium or volume depletion
9. Primary aldosteronism.
10. Hereditary fructose intolerance
11. Biliary obstructive disorders (e.g., cholestasis) or hepatic insufficiency
12. Congestive heart failure New York Heart Association functional class Congestive Heart Failure III-IV (Refer to Appendix 10.3)
13. Contra-indication to a placebo run-in period (e.g., stroke with-in the past 6 months, myocardial infarction, cardiac surgery, percutaneous transluminal coronary angioplasty, unstable angina or coronary artery bypass graft within the past 3 months prior to start of runin period)
14. Clinically significant ventricular tachycardia, atrial fibrillation, atrial flutter or other clinically relevant cardiac arrhythmias as determined by the Investigator
15. Hypertrophic obstructive cardiomyopathy, severe obstructive coronary artery disease, aortic stenosis, hemodynamically relevant stenosis of the aortic or mitral valve
16. Patients whose diabetes has not been stable and controlled for at least the past 3 months as defined by an Glycosylated Hemoglobin >=10%
17. Patients who have previously experienced symptoms characteristic of angioedema during treatment with ACE inhibitors or angiotensin-II receptor antagonists
18. History of drug or alcohol dependency within 6 months prior to signing the informed consent form
19. Concomitant administration of any medications known to affect blood pressure, except medications allowed by the protocol
20. Any investigational drug therapy within 1 month of signing the informed consent
21. Known hypersensitivity to any component of the trial drugs (telmisartan, hydrochlorothiazide, or placebo)
22. History of non-compliance or inability to comply with prescribed medications or protocol procedures (less than 80% or more than 120%, especially during run-in)
23. Any other clinical condition which, in the opinion of the investigator, would not allow safe completion of the protocol and safe administration of the trial medication