A variety of oxides were examined as additives to a V2O5/TiO2 catalyst in order to enhance the catalytic performance for the vapor phase oxidation of toluene to benzoic acid. It was found that the modification with SeO2, TeO2 or Sb2O3 greatly promoted the title reaction leading to improved catalyst performance in terms of toluene conversion and benzoic acid selectivity. The effect of reaction temperature, O-2/toluene ratio, steam/toluene ratio and durability were also investigated in order to reveal the catalytic features of the modified catalyst systems.