Abstract: The present invention relates to a process for producing a capacitive hygrometer, as well as to a hygrometer obtained by this process.Onto a conductive layer forming the first electrode is deposited a layer of a material with a dielectric constant varying as a function of the quantity of water absorbed. Onto the said dielectric material layer is then deposited a layer with a thickness exceeding 200 .ANG. of a slightly oxidizable metal, which forms the second electrode. The latter is made permeable to water by heat treatment at a temperature close to the softening temperature of the dielectric.Application to the measurement of the relative humidity of air.