This paper deals with the influence of the echographic probe pressure on the measurement of arterial diameter. It is common sense that arterial diameter measurements are affected by the pressure exerted on the B-mode ultrasound probe but we found no report in the current literature analyzing and quantifying this effect. We demonstrated this influence by the analysis of arterial images obtained with a conventional B-mode ultrasound system while monitoring the pressure exerted on the probe with a force sensor. Our preliminary results demonstrated that continuous measurement was feasible and could be used to assess the relationship between the blood pressure and the arterial diameter. This may prove useful for the quantitative evaluation and the follow-up of patients with cardio-vascular diseases.