Adsorption of strontium on illite type clay has been studied as a function of shaking time, the ratio of solution volume to weight of clay and the concentration of adsorbate, using Sr-90 as a tracer. The adsorption experiments were carried out using the batch method and initial Sr2+ ion concentrations ranged from 10(-6) to 10(-1) M. The influence of Ca2+ and Ba2+ cations on Sr adsorption were also studied. These effects are correlated with the ionic radii of alkaline earth ions present in the solution. The Freundlich and Dubinin Radushkevich (D-R) isotherm have been applied to the data and the parameters of the isotherm equations were calculated. The mean energy of adsorption, E was also calculated from the adsorption energy constant, K and maximum capacity X-m values were determined from linearized D-R equation. From empirical Freundlich parameters a site distribution function was calculated.