Ah&met-The sequential deposition of two metals Me' (Me' = Ag) and Me" (Me" = Pb or Tl) on polyand single-crystal gold substrates was studied using the dipping technique and potential sweep voltammetry. In a first step, silver was deposited in submono-, mono-, or multilayer amounts under extreme diffusion contolled conditions at tixed under-and overpotentials. Using ex situ STM measurements, these thin silver films were found to be very regular even on an atomic scale, with a structure identical to that of the underlying gold substrate. In a second step, the deposition of Me" was performed cychc-voltammetrically in the corresponding underpotential region. From the peak structure of the Me" desorption voltammogram it can be concluded that the Ag fdm is epitaxially deposited. After the deposition of 2-3 silver monolayers the gold single crystal substrate is totally transformed into a silver singlecrystal substrate. At lower degrees of silver coverage the Me" voltammograms exhibit contributions which are typical of both gold and silver substrates. If the sequential order of deposition of both metals is reversed, which means the silver is plated subsequent to the formation of a monolayer of Me" adatoms, the desorption spectra exhibit a structure which is typical of the upd of Me" on a Ag substrate, which means that the Ag atoms must have penetrated the Me" layer.