The catalytic activity of Pd-supported catalysts over Ce0.39Zr0.61O (x) /SiO2 was studied by using methane combustion reaction. UV-visible and TPR results showed the presence of large PdO particles. CO/Pd ratio decreased with the increase of metal load. The light-off temperatures indicated that high Pd loading favored the reaction. The reduction treatment decreased the activity suggesting loss of the active phase.