Waste water treatment is particularly i mportant from an environmental perspective. In this study, industrially produced Duolite ion-exchange resin was modified with iron oxides, and the resulting composite was used to adsorb chromium(VI) ions from aqueous solutions. The composite was produced using co-precipitation of iron salts in the presence of the ion-exchange resin. The effect of the initial concentration of the metal ion in the solution on the process was determined. Based on theexperimental results, sorption isotherms were plotted, and Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Halsey models were applied. It was found that the Freundlich and Halsey models describes the adsorption better. The correlation coefficient for both models is 0.9866. The Freundlich isotherm constant is 2.38 (mg/g)∙(l/mg)1/n; the non-uniformity coefficient is 0.8452. This result indicates that the process occurs at energetically different active centers, which is related to the structureof the composite.