Nitroindoles give polymer films after oxidative electropolymerization on a Au rotating-disc electrode in acetonitrile. Films of poly(4-nitroindole) and poly(5-nitroindole) were grown potentiostatically at potentials where electrodissolution of Au substrate occurs simultaneously with the electropolymerization. The films are electroactive. Their cyclic voltammograms in acetonitrile present an immense cathodic peak corresponding to the reduction of the nitro group. On transfer to aqueous electrolyte, films of poly(5-nitroindole) show well-defined reduction peaks, while those of poly(4-nitroindole) show ill-defined peaks. The reduction of the nitro group of the monomers has also been studied. Nitroindoles show the usual behaviour of aromatic nitro compounds both in aqueous solutions and in acetonitrile. Finally, it was found that underpotentially deposited layers of Pb and Tl on Au and Pt have a marked influence on the catalytic activity and selectivity of these electrodes for the nitro group electroreduction.