Thin films of poly(vinyl chloride) (PVC)-poly(methyl methacrylate) (PMMA) blend with lithium triflate (LiCF3SO3) salt and dibutyl phthalate (DBP) as plasticizer were prepared by solution casting method. The conductivity and dielectric measurements were carried out on these films as a function of frequency at various temperatures. The addition of DBP significantly improved the ionic conductivity. The conductivity-temperature plots were found to follow an Arrhenius nature. The dielectric behaviour was analysed using dielectric permittivity (epsilon'), dissipation factor (tan delta) and electric modulus (M') of the samples.