The work investigates the effect of mechanochemical activation (MCA) on the structure and properties of vermiculite. The process of activation is controlled by X–ray diffraction (XRD), IR–spectroscopy, and scanning electron microscopy. The thermal stability of the vermiculite was studied by the differential thermal analysis. It was found that an increase in the degree of MCA of vermiculite makes it possible to change the vermiculite hydration states and its mica package passed into a zero hydration state, one– or two–layer state. In the study of the samples sorption capacity as related to oil products, it was shown that adsorption proceeded according to a competitive mechanism. The linearization of experimental data on the adsorption of oil products was achieved in linear coordinates of the Freundlich isotherm, that confirmed adsorption in the volume of energetically inhomogeneous porous adsorbent. A positive effect of MCA on the sorption capacity of the samples was noted. Display omitted •In the process of mechanochemical activation of vermiculite, the processes associated with dispersion and stratification of the mica package of the mineral were observed, an increase in the degree of mechanochemical effect on vermiculite allows to change its hydration states, contributing to the transition toward a zero hydration, one– or two–layer state.•Mechanochemical activation of the samples does not only change the phase structure of vermiculite, but also significantly changes its physicochemical properties, contributing to the growth of acid–base sites on the surface, specific surface area.•A positive effect of mechanochemical activation on the sorption capacity of samples based on modified vermiculite in relation to oil products was noted.