Fast protonic conductors were prepared in the P2O5-containing silicate glasses using the sol-gel method. The 5P(2)O(5). 5ZrO(2).90SiO(2) glasses, obtained by heating at 200 to 800 degrees C, were crack-free and chemically stable and exhibited room temperature conductivities of 10(-3) S/cm, which were higher by similar to 5 orders of magnitude than that of the dried gel or porous silica glass. These high conductivities were regarded as the fast proton mobility accelerated by molecular water which was chemically bonded with POH groups.