Ambulatory blood pressure monitoring is increasingly used in clinical evaluation of the hypertensive patient. The aim of the present study is to investigate the accuracy of non-invasive blood pressure measurements provided by the Profilomat, a new portable, automatic blood pressure recorder, in normotensive subjects and hypertensive patients. The results showed a good correlation between the blood pressure values measured by this apparatus and those determined simultaneously by the conventional auscultatory method (sphygmomanometer). Thus, the Profilomat appears to be a useful instrument for study of arterial blood pressure outside the doctor's office.