Bimetallic Au-Pt nanoparticles (Au-Pt-Nps) have been synthesized using an electrochemical reduction approach. The effects of the addition of different additives in the electrodeposition bath namely KI, 1-nonanesulfonic acid sodium salt and Triton X-100 have been investigated. The structural characterization of the bimetallic nanoparticles has been carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS). UV-vis spectroscopy, X-ray diffraction (XRD) and cyclic voltammetry (CV). The Au-Pt-Nps prepared in the presence of KI and Triton X-100 characterized by a relatively narrow size distribution as well as a higher particle density and surface coverage whereas no changes in the morphology were observed. These results suggest a dependence of the size and distribution of the bimetallic nanoparticles from the type and concentration of the additives employed. (c) 2010 Elsevier Ltd. All rights reserved.