Diesel soot oxidation over Au-VOx/TiO2 and Au-VOx/ZrO2 catalytic systems with different vanadia loadings were studied. The heavy-duty diesel soot was preliminarily analyzed. The composition of the catalysts was investigated by means of FT-Raman. Their activity toward the oxidation of diesel soot was assessed by thermogravimetrical analysis. The combustion onset temperature and the combustion peak maximum can be lowered to 361 and 419degreesC, respectively. Reaction rates R at certain temperature T-r are calculated out of the first derivative from the mass loss in function of temperature (TGA plot). The results of the activity tests indicate a synergistic effect between Au nanoparticles and vanadia when VOx presents as a monolayer on the support. Catalysts with higher V loadings show a higher activity but no synergistic effects between Au and V could be observed.