Nanosized anatase TiO2 has been prepared by a sol-gel hydrothermal process. The effect of water:alkoxide molar ratio, hydrothermal aging temperature and aging time on the properties of the nanocrystalline anatase TiO2 was investigated in detail. The specific surface area, sulfur content and surface acidity of sulfated titania catalysts prepared by sulfation of sol-gel hydrothermal derived nanocrystalline TiO2 were greater than those of the analogous catalyst prepared from ordinary amorphous titania hydrate. The former catalysts displayed higher catalytic activities in isopropanol dehydration, cumene cracking and n-pentane conversion reactions, The influence of the crystalline state and crystalline grain of titania precursors on the properties of sulfated titania catalysts was studied and discussed. (C) 2002 Elsevier Science B.V. All rights reserved.