PVA (Polyvinylalcohol) based hybrid membranes were prepared by incorporating inorganic fillers and ionic liquids (ILs) like 1-butyl-3-methylirnidazolium Bis (trifluoromethanesulfonyl) imide (BMITFSI) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF4) using sol-gel method. Hybrid composite membranes were investigated with respect to its structural and thermal properties, water uptake capability and proton conductivity. TG-DTA studies confirmed the thermal stability of membranes and both ILs based membranes are stable up to 370 degrees C. As compared between two ILs, EMI-BF4 contained membranes showed better thermal stability and a complete degradation of main chain polymer backbone is occurred at about 640 degrees C. Thus, the thermal stability of the membranes was importantly enhanced by the presence of both EMI-BF4 and SiO2. From the experimental data, the conductivity of PVA based hybrid membranes depends on the ILs and its concentration. Significantly, the maximum conductivity of PVA/PMA/SiO2/BMITFSI and PVA/PMA/SiO2/EMI-BF4 hybrid membranes at 60 degrees C were 0.83 x 10(-3) S/cm and 0.58 x 10(-3) S/cm with constant relative humidity of 50%, respectively. It was found that, the proton conductivity essentially reduced with an increasing ILs fraction accompanied with the increase in cross-linking density, which impedes the proton conductivity due to the enhanced compact nature of membranes. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.