Ionic conductivity of poly(vinylchloride) (PVC)/poly(methylmethacrylate) (PMMA) blended electrolytes containing LiCF3SO3 and LiBF4 has been studied using a.c. impedance spectroscopic technique. The: variation of conductivity has been investigated as a function of polymer blend ratio, plasticizer content, ethylene carbonate (EC) and propylene carbonate (PC) and lithium salt concentration at 25, 40, 50 and 60 degrees C. Electrolyte films showing conductivities in the 10(-3) S cm(-1) region have been obtained, A 7:3 PMMA/PVC blend electrolyte at 70% plasticizer content has been found to possess optimal properties in terms of conductivity and mechanical strength.