The effect of the palladium precursor on the CO and NO adsorption capacity of Pd-MoO3/Al2O3 catalysts was studied. TPR and LR analysis showed that the palladium addition promoted the reduction of Mo6+ to Mo4+. The presence of a higher amount of molybdenum oxide partially reduced improved the NO dissociation to N-2 and N2O on Pd-Mo/Al2O3 catalysts. This behavior was attributed to the formation of a lower fraction of inactive adsorbed nitrogen species on molybdenum oxide partially reduced. The catalytic behavior of the Pd-Mo/Al2O3 catalysts on the NO + CO reaction could be explained by a bifunctional mechanism. After adsorption and dissociation of NO on Mo4+, the oxygen dissociated is transferred to the Pd. The CO adsorbed on the Pd surface reacts to CO2.