A process of fully competitive ion exchange of Fe (III) and Zn (II) ions in zeolite NaY from multicomponent systems is described and compared to the uptake of single metal ion. The experiments were carried out in an up flow fixed beds at 30°C. It was seen that the single isotherms, provided by the breakthrough curves, generated a favorable behavior with a maximum uptake of 2.65 meq/g and 3.20 meq/g for iron and zinc single solutions, respectively. It means that differences in such behavior are due to the steric problems experienced by both hydrated ions. The competing systems for a range of concentration ratio zinc/iron also showed a preference for the divalent ion. The single and competing ion exchange processes were modeled considering the intraparticle diffusion as the rate-controlling step. The axial dispersion coefficient and the mass transfer coefficient were estimated. It was seen that the numerical values for both coefficients reflected the preference for the divalent ion.