Hypertension is one of the most common primary diagnoses and a known risk factor for cardiovascular disease, stroke and kidney disease. Like many other physiological variables, blood pressure is characterized by long- and short-term variability. Thus, blood pressure measured over extended periods of time, i.e. ambulatory monitoring, is more representative of the actual value than a single office reading. In longitudinal studies, ambulatory blood pressure (ABP) is found to predict future cardiovascular risk better than conventional blood pressure. Not only blood pressure values but also the pattern predicts cardiovascular risk on ABP measurement. Non-dipping blood pressure pattern, i.e. night-time/daytime pressure greater than 0.9, is an independent risk factor for cardiovascular events. Ambulatory blood pressure is vital for identifying specific conditions such as white coat hypertension, masked hypertension, and apparent drug resistance. Recognizing these conditions is important considering the fact that they have significantly different prognosis than predicted from conventional office readings in each condition.