Sodium ion conducting composite polymer electrolytes (CPE) have been prepared by solution casting technique in the skeleton of polyvinylidenefluoride-co-hexafluoropropylene/poly ethyl methacrylate blend. The binary Mixture of diethyl carbonate and ethylene carbonate were used as plasticizer, and nanosized Sb2O3 as filler. The sodium trifluoromethanesulfonate (NaCF3SO3) Was used as an ionic conducting source. The a.c. impedance study shows that 10 wt% Sb2O3 containing CPE exhibits the maximum conductivity 0.569 mS cm(-1) at ambient temperature. Molecular interactions of the constituents Were analyzed by Fourier transform infra red spectroscopy. X-ray diffractogram reveals the amorphous nature of the CPE. A surface morphological feature was studied through scanning electron microscope. The activation energy and coherence length calculated were in support of the ionic transport. (C) 2008 Elsevier B.V. All rights reserved.