We report the electropolymerization of CuPtBr 6 film on the electrode substrate by cyclic scanning in 3x10 - 3 M CuCl 2 +3x10 - 3 M K 2 PtBr 6 +1 M KCl in the potential range from +700 to -800 mV (versus the saturated calomel electrode (SCE)). Several surface analysis techniques were used to characterize the film on the electrode surface. A sharp and intense diffraction peak in the X-ray diffraction (XRD) pattern indicates that the film has a high preferential orientation. The electrochemical behavior of the modified electrode was studied in detail in electrolyte solutions containing various cations. On the basis of these studies, a mechanism of electropolymerization was proposed which suggests for the modifier film a one-dimensional, polymeric structure formed from a negatively charged platinum compound, stabilized by Cu 2 + and Cu + as the counter ions. The composition of the modified film is proposed to be [CuPtBr 6 .CuPtBr 4 ] n , and is denoted as CuPtBr 6 /glassy carbon (GC) to highlight the starting components. H + /H, Fe 3 + /Fe 2 + and Cr 3 + /Cr 2 + display remarkably reversible redox behaviors at the CuPtBr 6 /GC electrode. The modified electrode also displays good catalytic activity toward the oxidation of ascorbic acid, hydrogen peroxide, S 2 O 3 2 - , and especially nitric oxide.