Thin Sn-O-Te films with a thickness of 60 nm have been deposited by co-evaporation of Sn and TeO2 on alumina substrates with interdigitated silver-palladium electrodes. During the co-evaporation a chemical reaction between the two substances takes place, resulting in the formation of a Sn-oxide matrix and finely dispersed phases of Te, Sn, TeO2 or SnTe, depending on the atomic ratio of Sn to Te (R-Sn/Te). To study the morphology and structure as well as to determine the atomic ratio R-Sn/Te of the films, electron microscopy techniques (TEM, SAED) and analytical methods (EDS in SEM) have been applied. The electrical properties of the sensors studied have been investigated in the frequency range of 20 Hz - 5 MHz using a Precision Impedance Analyzer. The measurements have been taken on samples placed in a controlled humidity and temperature chamber. The characteristics of the resistance R, capacitance C, impedance z and phase theta as functions of relative humidity RH%, the frequency dependences of R, C, z and center dot, the Nyquist plots and equivalent electrical circuits of the sensors have been obtained. As a result, the relation between the type of water adsorption, impedance spectra and the properties of the films as humidity sensors are presented in this paper.