24-hour ambulatory blood pressure measurement (ABPM) provides more representative information than office blood pressure measurement on cardiovascular risk and the risk of target organ damage. ABPM makes it possible to assess arterial pressure during the whole of the nycthemere and to assess the different characteristics of the latter (nocturnal dipping, lability, hypotension) without requiring significant intervention on the part of the patient. ABPM makes it possible to make specific diagnoses such as arterial hypertension of the white coat and masked hypertension, and thus adapt the therapeutic attitude accordingly.