In this paper, we used a simple hydrothermal treatment at 100 degrees C to introduce the meso-voids into the silica spheres templated. by the low-toxicity poly(ethylene oxide) homopolymers. The generation of the meso-voids is ascribed to the mismatching interactions between the siloxane groups on the further condensed silica wall and the ether groups in PEO polymers upon hydrothermal reaction. The void size in the silica spheres is dependent on the pH values of the hydrothermal solution and increases with increasing the pH value. Because of the existence of the interconnective meso-voids, the hydrothermally-treated PEO-silica spheres can be directly used as the template for mesoporous carbon without removing the PEO polymers. After PF polymer-impregnation, curing, pyrolysis and HF-etching, the mesoporous carbon spheres of high surface area and pore volume were obtained. (c) 2005 Elsevier B.V. All rights reserved.