Composite polymer membranes comprising of poly(vinylidene fluoride-hexafluoro propylene)/alumina (PVdF-HFP/Al2O3) were prepared by phase inversion technique with poly(ethylene glycol) (PEG) as an additive. The prepared membranes were soaked in 6M H3PO4 and were immobilized for protonic conductivity. The morphological properties of the prepared membranes were examined by scanning electron microscopy (SEM). The infra-red spectroscopic measurements revealed the presence of phosphate anions in the composite membranes. The ionic conductivity of the membranes has also been measured. The protonic conductivity of the membrane has considerably been increased upon the incorporation of ceramic filler (Al2O3). The polymer membrane prepared with a weight ratio of PVdF-HFP (40):PEG (40):Al2O3 (20) showed maximum protonic conductivity due to the combined effect of inert filler and its porous nature. (c) 2007 Elsevier B.V. All rights reserved.