The development and reconstruction of surface structures formed by underpotential deposition (UPD) of Cu atoms on Pt(100) and Pt(111) clusters are approached through extended Hückel molecular orbital (EHMO) calculations applied to a statistical Cu atom deposition. These results allow us to obtain a qualitative description of the different stable configurations of Cu atoms on the Pt cluster surfaces in terms of the corresponding binding energies.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas