Polyelectrolyte-functionalized ionic liquid (PFIL) and Prussian blue (PB) nanoparticles were used to fabricate ultrathin films on the ITO substrate through electrostatic layer-by-layer assembly method. Multilayer growth was examined by UV-vis spectroscopy and cyclic voltammetry. The resulting ITO/(PFIL/PB)n electrode showed two couples of well-defined redox peaks and good electrocatalytical activity towards the reduction of hydrogen peroxide. The obtained PFIL/PB multilayer showed excellent reproducibility, good stability and high sensitivity (even to 10(-7) M) for the amperometric analysis of hydrogen peroxide. In comparison with a similar Poly(diallyldimethyldiammonium chloride) PDDA/PB multilayer, it was found that the PFIL played an important role for the electrocatalytical reduction of hydrogen peroxide. (c) 2008 Elsevier B.V. All rights reserved.