Mixed WO3-TiO2 oxides have been prepared from aqueous solutions of tungstic acid and titanium isopropoxide in H2O2. Peroxopolytungstic acids 'WO3 . H2O2 . H2O' are obtained from pure tungstic acid whereas WO3 . 1/3H(2)O is formed in the presence of Ti-IV. Three crystalline oxides are formed successively upon heating Ti doped WO3 . 1/3H(2)O, namely h-WO3, o-WO3 and m-WO3. The intermediate metastable o-WO3 phase has not been observed in the absence of titanium. The cathodic behavior of these oxides shows that the discharge curves corresponding to the electrochemical insertion of Li+ are noticeably different. This has to be related to the structural differences between these phases.