A high proton-conducting PMMA-SiO2-P2O5 (75-20-5 wt.%) membrane with a conductivity of 1.35 x 10 (1) S cm (1) at 90 degrees C for value of relative humidity of 50% was prepared and an excellent thermal stability was found by hybridizing phosphosilicate with PMMA using the sol-gel technique. This is one of the most promising ways to obtain high performance proton-conducting hybrid membranes. (C) 2011 Elsevier B. V. All rights reserved.