Inadequate control of blood pressure during antihypertensive treatment remains a major problem in preventive cardiovascular and renal disease. Major causes of resistant hypertension are following: problems in measuring technique, presence of white coat effect, poor adherence of patient, obesity, excessive alcohol intake, sleeping apnea syndrome, excess of body fluid, inappropriate use of hypertensive or anti-antihypertensive drug/supplement, especially their combination, and presence of secondary hypertension. Practitioners have to seek for the causes around their patients' lifestyle, prescription, secondary hypertension, after ruling out pseudo-hypertension or white coat hypertension. Evaluation of complications is also important in management of resistant cases, because of their high prevalence of target organ damage.