Catalysts that are very active and selective in the oxidative dehydrogenation of ethanol to acetaldehyde have been prepared by grafting vanadyl triisopropoxide onto a silica support whose surface was coated with TiO2. Together with acetaldehyde, small amounts of byproducts were obtained, including acetic acid, acetals, and CO2. The kinetic behaviors of the catalysts were studied in the temperature range 100 - 180 degreesC, by changing the ethanol residence time, the molar ratio between the reagents, and the vanadium load. A four-step mechanism was adopted, consisting of the following steps: (i) dissociative adsorption of ethanol onto vanadium, (ii) alpha-hydrogen withdrawal by the metal to form acetaldehyde and a hydride group, (iii) oxidation of the formed hydride, and (iv) dehydration of the vanadium site to restore the original active site. This mechanism can be simplified, and the resulting kinetic expression is similar to a Mars and van Krevelen kinetic expression. The reaction is well-described by this kinetic model. The activation energy (11 kcal/mol) obtained for the main reaction is in agreement with the values reported in the literature for the same type of catalyst. The reaction rates depend linearly on the vanadium load.