Polyester polyol/titania hybrid resins and their corresponding polyurethane/titania hybrid films were prepared by in situ method via sol-gel process of titanium n-butoxide under acidic condition. The effects of the contents and types of titania sol on the microstructure and some mechanical and optical properties of the hybrids were investigated. It was found that introducing titania into the resin could increase some physical properties such as the viscosity of the resin, modulus, T-g, mechanical strength, abrasion resistance, hardness and UV absorbance, but different titania sols obtained from various molar ratios of water to titanium n-butoxide had an obvious influence on the microstructure and properties ofthe hybrid films. (c) 2006 Elsevier Ltd. All rights reserved.