The thermal decomposition of vanadyl oxalatesupported on CeO2 solid in a flow of dried air was analysed by thermogravimetry (TG) and differential scanning calorimetry (DSC) from room temperature up to 350C. TG and DSC results have demonstrated that after the impregnation of CeO2 solid by a vanadyl oxalate solution, cerium and vanadium(V) oxalates were evidenced. This latter compound seems attached to cerium(III) of the partial reduced CeO2 phase. This result was confirmed with the electron paramagnetic resonance(EPR) and X-ray photoelectron spectroscopy (XPS) techniques.