The first synthesis of poly(styrene-co-styrylethyltrimethoxysilane)[P(ST-STMS)]-silica hybrid materials has been achieved via the acid-catalyzed sol-gel reactions of P(ST-STMS) with tetraethyl orthosilicate. New sulfonated polystyrene-silica hybrid materials have been prepared by sulfonation of P(ST-STMS)-silica and poly [styrene-co-3-(trimethoxysilyl)propyl methacrylate]-silica hybrids with concentrated or fuming sulfuric acid. The sulfonated materials exhibit cation exchange capacities ranging from 0.33 to 1.27 meq/g depending on the composition of the hybrid materials and an the sulfonation conditions.