A kinetic study of the partial oxidation of o-xylene over a V2O5/TiO2 catalyst in a fluidized bed reactor is presented. The use of a fluidized bed reactor allows to obtain reliable kinetic data in spite of the strong exothermicity of the reaction. The effect of the main operating variables has been studied. Additionally, a fluid-dynamic model for both phases (gas and solid), able to describe their behaviour in fluidized beds has been used to fit data. Two redox kinetic models have been tested: the first one takes into account only oxidized sites, while the second one considers both, oxidized and reduced sites.