In the present work, proton exchange membranes are obtained from n-butyl acrylate/styrene copolymer modified with ferric oxide (Fe2O3) for its use in fuel cells. The physicochemical and mechanical properties of each membrane were characterized. The addition of Fe2O3 increased water retention, ion exchange capacity and Young's modulus due to the hydrophilic character contributed to the ferric oxide which through the formation of hydrogen bonds allowed an adequate interaction between the load and the polymeric matrix. The modification of the copolymer was identified through the FTIR analysis. The synthesized membranes have potential as an electrolyte in the fuel cell, however it is necessary improve its mechanical properties.