The contribution of the Interface Science to the preparation of supported catalysts during the last two decades is presented. It is illustrated how the concepts and the methodologies of the Interface Science could be effectively used for an in-depth understanding of the phenomena involved in the initial preparation step. This, extremely critical step, concerns the deposition of transition metal species containing the active elements, from an impregnation solution, onto the surface of common catalytic supports. Moreover, the aforementioned concepts and methodologies allow the regulation of the mode of interfacial deposition and the local structure of the deposited species and, thus, the surface characteristics and the catalytic behaviour of the resulted catalysts.