Au/n-GaAs Schottky barrier diodes SBDs have been fabricated. Schottky diode parameters such as the ideality factor, the series resistance, and the Schottky barrier height (SBH), Phi(b), have been measured as a function of hydrostatic pressure using the current-voltage (I-V) technique. We have seen that the SBH has a linear pressure coefficient of 11.21 meV/kbar (=112.1 meV/GPa). Also, the series resistance value increases with increasing pressure. We have concluded that the variation of the barrier height due to the applied pressure should follow precisely the variation of the semiconductor band gap, accepting that the Fermi level is a reference level which is pinned to the valance-band maximum as a function of the pressure. That is, we have concluded that the experimental results is in agreement with the model that the pressure coefficient is caused by the pressure coefficient of the direct midgap level. [S0163-1829(99)07643-2].