The development of a simple and efficient method to 2-(2-nitrophenyl)-1H-benzimidazole (NB) electrochemical determination using a polymer film coated chemically modified electrode is described. A glassy carbon (GC) electrode was modified employing an electro-polymerized film of 1-naphtylamine (1-NAP) followed by an over-oxidation treatment in 02 M sodium hydroxide solution (poly-1-NAPox electrode). The electrochemical behaviour of NB at the poly-1-NAPox electrode was investigated in a mixture of 10% ethanol + 90% buffer solution (pH 2) by cyclic voltammetry (CV) and square-wave voltammetry (SWV). The experimental results suggested that the poly-1-NAPox electrode had a good effect on NB electrochemical response because it avoided the electrode surface fouling as a consequence of the adsorption of NB reduction products, which was found when a bare GC electrode was employed as the working electrode. The NB cathodic current was dependent on the polymeric film over-oxidation degree (alpha). NB could be determined in the range from 2 x 10(-6) to 5 x 10(-5) M. The NB detection and quantification limits were 5 x 10(-7) and 1.7 x 10(-6) M. respectively. The percent relative standard deviation of the peak current to 10-replicated measurement using 1 2 x 10(-5) M NB solution was 1.4%. The method showed to be rapid, simple and with a good sensitivity. (C) 2010 Elsevier Ltd All rights reserved.