The coating nanomixed oxides CeO2-Mn2O3 on activated charcoal was synthesized by sol-gel method combustion method using polyvinyl alcohol (PVA). The percentage of mixed oxides in materials was varied at 8, 10, 12 and 15 %. Optimum conditions were applied to synthesize materials which is molar ratio of Mn2+/Ce4+ =1/1. Gel formation was obtained at temperature of 80oC, molar ratio of (Mn2++Ce4+)/PVA=1/3 pH 4 and calcination temperature of 350oC for 2 hours. The Ce(IV) concentration of synthesized material was determined by titration method using diethylene triamine pentaacetic acid (DTPA) with asenazo indicator. Whereas, Mn(II) concentration was determined by atomic absorption spectrophotometry on Perkin Elmer Analyst 200 at wavelength of 279.5 nm. Arsenic and ammonium adsorption on materials were illustrated. The adsorption capacity of As(III) and ammonium by nanomixed oxides on activated charcoal is 4.10 mg/g and 2.89 mg/g, respectively. From the results, these composite materials promises a great application to treat As(III) and ammonium in aqueous solution.Keywords: CeO2 – Mn2O3, PVA, sol – gel, ammonium, arsenic, adsorption.