In this work, we study the simultaneous polymerization of vinylic monomers initiated via the electrografting of suited precursors on metallic substrates. The outcome of this work is to be able to obtain, in one step, new modified substrates with various surface properties brought by the combination of both polymers. For that purpose, two different vinylic monomers were simultaneously submitted to electro-initiated grafting on metallic electrodes, which mechanism is now well documented. We studied several couples of monomers chosen among four molecules: acrylonitrile, methacrylonitrile, methyl methacrylate and glycidyl methacrylate. In order to achieve simultaneous electrografting of both monomers, it is necessary to take into account the following molecular parameters: (i) the respective reduction potentials of the two monomers, (ii) the relative nucleophilicity of the anions propagating the reaction, (iii) the molecular structure of the neutral molecules. In this work, we discuss the influence of all of these parameters thanks to cyclic voltammetry, chronoamperometry, infrared measurements and quantum chemistry computational calculations. Association of experimental and computational results leads to a better understanding of the process. (c) 2005 Elsevier B.V. All rights reserved.