The first results of determination of the content of different types of bound water by hygrometric method — adsorption isotherm method — for extracted rock samples of Bazhenov formation are presented. All obtained water sorption isotherms have a well-defined S-shape, which allows to determine the maximum possible amount of bound water of different types (mono -, poly-and capillary condensation) in all studied samples. The inflection points of the isotherms of the extracted samples fully correspond to the inflection points of the isotherms of the native samples. Based on the obtained results, it is possible to further estimate the specific surface area of the samples, and then determine the hydrophobicity coefficient and the parameters of the associated oil saturation.