Ambulatory blood pressure measurements may be performed with manual or automatic devices. Such methods seem to be increasingly used for diagnosing conditions like "white coat hypertension" or abnormal variations in the 24-hour blood pressure profile. However, it is not yet known whether these patients are exposed to an increased risk of cardiovascular events.This paper is a summary of systematic reviews (health technology assessment reports) of the performance and effectiveness of ambulatory blood pressure measurements for the diagnosis of hypertension.Ambulatory blood pressure measurements may be used during medical treatment for hypertension to control blood pressure, and patients using these measurements have been shown to reach the target blood pressure at lower medication levels than patients depending on blood pressure measurements in the surgery.Widespread use of ambulatory blood pressure measurements in order to predict cardiovascular risk requires knowledge about diagnostic and prognostic performance. There are studies that address these concerns, but major weaknesses in study design limit their value. The lack of a consensus on reference values is also an impediment to the use of ambulatory blood pressure measurements.