Sorption and diffusion processes with134Cs and85Sr in natural bentonites have been investigated. The distribution coefficients (Kd) have been determined by a batch method. Various factors affecting theKd value as water-to-bentonite ratio, concentration of the competitive cations in the aqueous phase or bentonite-to-sand ratio
in the mixed sorbents have been evaluated. A comparison of the sorption and diffusion data has been made.