Ambulatory blood pressure monitoring (ABPM) measures blood pressure at regular intervals. It is believed to be able to reduce the white coat hypertension effect in which a patient's blood pressure is elevated during the examination process due to nervousness and anxiety caused by being in a clinical setting. ABPM can also detect the reverse condition, masked hypertension, where the patient have normal blood pressure during the examination but uncontrolled blood pressure at home. Out-of-office measurements are highly recommended as an adjunct to office measurements by almost all hypertension organizations.

The instrument used is a portable blood pressure machine worn as a belt, with the cuff being attached around the upper arm. All types of daily activities, including sleep, may be normally carried out while wearing this device.