The oxidative decomposition of trichloroethylene(TCE) over supported platinum and transition metal oxide catalysts was examined in a fixed-bed flow reactor system. When Pt catalysts impregnated on various types of support were employed for the decomposition reaction, the formation of perchloroethylene(PCE) as a by-product was frequently observed during the course of reaction. The Pt/TiO₂ catalyst exhibited a better performance than the Pt impregnated on the other supports. Over the TiO₂-supported catalysts, the decomposition activity depended on the types of active component, and the activity decreased in the order of CrO_x(98 %)>MnO_x(79%)>Pt(72%)>CoO_x≈CuO_x(58%)>FeO_x(54%)>NiO_x(49%) at 400℃. Perchloroethylene was not formed over chromium oxide catalysts, regardless of the types of support employed in the present work. Therefore, CrO_x/TiO₂ catalyst is the most effective for the oxidative decomposition of TCE under the experimental conditions covered in the present study. Although the effect of H₂O on the decomposition of TCE over CrO_x/TiO₂ catalyst depends on the reaction temperature, it is completely reversible during the course of reaction. This indicates that the activity loss of the catalyst under the wet stream is probably due to the competitive adsorption of H₂O and TCE on the catalyst surface. Based upon the decomposition activity of TCE over the catalysts containing 1 to 30 wt% of CrO_x about 10 wt% of the loading is optimal for this action. The reaction kinetics of the oxidative decomposition of TCE over CrO_x/TiO₂ catalyst is first order with respect to its feed concentration with the activation energy of 9.7 kcal/mol which is lower than those over the other catalysts employed in this study.