Abstract: Mandibular advancement measurement and positioning device provided with an instrument (1) with an upper slider (2) and a lower slider (3), means to measure and position the relative displacement of both sliders and two trays at one end of the instrument, one upper and one lower (11a, 11b), the trays being attached to each slider respectively, wherein the lower slider is divided into a fixed part (3a) and a pivoting part (3b) joined to the end of the fixed part (3a), being the upper and lower slider joined by means of a recess that allows a relative slide of both and wherein the pivoting part (3b) of the lower slider is provided with a vertical opening control (6). By means of the pivoting part and the opening control it is possible to measure and position the vertical opening.