Alumina-silica catalyst supports having substantially high surfaces areas are formed by extrusion, drying and firing of a plasticized batch including an alumina-silica powder component, acid, organic binder and water. The alumina-silica powder component can be formed either by the mixing of alumina- and silica-source powders or by forming a slurry therefrom which is spray dried to form a particulate material prior to batching.