The adsorption behaviour of thorium from aqueous solutions by natural adsorbents (clays and oil shales) has been investigated by a batch technique. The natural samples were characterized by X-ray powder diffraction and X-ray fluorescence. The thorium adsorption on natural adsorbents was studied as a function of shaking time (adsorption kinetics). The adsorption data from experiments were fitted with Langmuir (forms I, II and III), Freundlich, Elovich and Temkin isotherms. The equilibrium process was described by the Langmuir model very well. Comparison of the oil schales adsorption capacity and the clays adsorption capacity indicated that the oil schales had a higher selectivity for thorium removal.