Proton conductive inorganic -organic membranes supported by glass paper were prepared from 3-glycidoxypropyltrimethoxysilane, tetraalkoxysilane and orthophosphoric acid. Hybrid membranes with a thickness of 70-80 mu m were obtained by using two types of glass papers. The open circuit voltage of the test cell using the membrane supported by class paper was 0.75 V. A power density of about 80 mW cm(-2) was obtained with a current density of 300 mA cm(-2) at a cell temperature of 130 degrees C under 7% relative humidity. (c) 2005 Elsevier B.V. All rigths reserved.