The adsorption behaviour of Fe(II) and Mn(II) onto bentonite was studied as a function of temperature under optimized conditions of shaking time, amount of adsorbent, pH, and concentration of the adsorbate. Thermodynamic parameters such as Delta H-0 and Delta S-0 were calculated from the slope and intercept of the linear plot of In K-D against 1/T. Analysis of absorption results obtained at T = (298, 303, 313, and 323) K showed that the adsorption pattern on bentonite followed the Langmuir and Freundlich isotherm. A flame atomic absorption spectrometer was used for measuring the concentration of the metals.