The accurate assessment and appropriate management of blood pressure (BP) is critical for primary care physicians. Traditional office-based BP measurement has limitations that can be addressed, in part, through the use of ambulatory BP monitoring (ABPM). Because BP readings are provided at specific time intervals throughout a 24-hour period, ABPM represents a better picture of the normal fluctuations in BP levels associated with daily activities, including sleep. Blood pressure values obtained by 24-hour ABPM are a better predictor of cardiovascular risk than office-based BP measurements, and the technique can be used to discern white-coat hypertension and to evaluate masked, resistant, and pseudoresistant hypertension. It can also be helpful in the assessment of autonomic dysfunction and monitoring of a patient's response to antihypertensive therapy. Ambulatory BP monitoring is also being increasingly used in clinical trials that assess the antihypertensive effects of medications.