Polymer electrolyte films of poly(ethyl methacrylate) (PEMA) with ethylene carbonate (EC) as a plasticizer and ammonium iodide (NH 4 I) as an ion-donating salt have been prepared using the solution-cast technique. The electrical characterization of the films was performed by impedance spectroscopy. The highest obtained ionic conductivity at room temperature was 1.16 × 10 −5 S/cm with the composition of PEMA: NH 4 I (60:40) + 10% EC. The ionic transference number of the mobile ions estimated by the dc polarization method, and the H + ionic transference number was found to be ß0.85, which revealed that the conductivity species are predominantly ions. Likewise, the micrographs of the films were analyzed under an optical microscope. In addition, the charge carrier density (n) of the individual films was calculated on the basis of the dielectric constant study. C 2016 Wiley Periodicals, Inc. Adv Polym Technol 201 , , 21693; View this article online at wileyonlinelibrary.com.