The position of the arm in relation to the heart is one of the factors responsible for variations in arterial blood pressure. The purpose of this study was to confirm these variations and their diagnostic and therapeutic consequences. The blood pressure of 59 subjects was measured in supine position with or without support, this support being a device, recently developed by Swedish physicians, that brings the radial notch of the ulna at heart level. The results obtained confirmed the existence of variations in blood pressure values according to the position of the arm in relation to the heart. When measured with the support, blood pressure fell by 5 mmHg for systolic pressure and 4.6 mmHg for diastolic pressure. These results prove the need for standardization of blood pressure measurement in supine position. It is permissible to believe that at this moment a non-negligible proportion of patients (12 percent in our series) is either wrongly regarded as hypertensive or overtreated. In addition, the blood pressure variations induced by the brachial support should be taken into account in the analysis of future epidemiological studies. We conclude that using the brachial support can be recommended for a better evaluation of supine blood pressure measurements.