A pressure gauge for the range from several mm Hg down to the micron region is described. The new gauge, based on the properties of alternating gas discharges, measures pressure in terms of the frequency of a relaxation oscillator incorporating as the nonlinear element a glow discharge between electrodes immersed in the gas, the pressure of which is to be determined. A stability of 1% has been obtained; the robustness and simplicity of the instrument render it particularly suitable for rocket‐borne measurements at high altitude.