Natural andNa-formof heat-treated bentonitewas applied for the adsorption of copper (II) and cobalt (II) ions frommodel sewage at 20-65°Ctemperature range. At various temperatures equilibrium adsorption capacity of both natural and Na-form heat-treated bentonite samples were determined. Adsorption efficiency of the adsorbents was increased by increasing the temperature. It can be hypothesized by the reduction of swelling and dehydration. Also, the adsorption efficiency for the Cu2+ was greater than Co2+ in all studied solution concentration and temperatures. Modification of bentonite by cation exchange method led into higher gross capacity values, equilibrium coefficient of distribution and metal ion adsorption selectivity.