The ion-exchange equilibrium of cesium and strontium ions on clinoptilolites from different deposits — Dzegvi and Tedzami /Georgian SSR/, Beli Plast and Beli Bair /Bulgaria/ in different cationic forms of the sorbents /natural, sodium, calcium and ammonium/ is studied. The static ion-exchange capacities are determined. The sorption isotherms are plotted and the corresponding distribution coefficients are calculated. Mechanical characteristics which are important for the assessment of the technological use of the sorbents in dynamic conditions are determined. The clinoptilolite from Beli Plast deposit has the highest capacity in comparison with the other studied zeolites. The selectivity of the clinoptilolites from Bulgarian deposits is independent of the cationic form of the sorbent while the selectivity of the Georgian clinoptilolites strongly depends on the cationic form; the selectivity of the ammonium form of Tedzami sorbent is the highest.