In the present work was studied theoretically the chemical reactivity of gold clusters (Aun;n = 4, 5 y 6) and gold-silver clusters (AunAg; n = 4, 5 y 6) at B3LYP/LANL2DZ level oftheory using global and local reactivity descriptors in order to analyze reactive behavior ofthese metallic systems. It was found that the size and doped with silver atom, influence thereactivity of the clusters studied. Also was found that the position of the silver atom in thecluster affects reactivity, being high when this is in the edges of the cluster and low when itoccupies a central position.