Modified electrodes composed of the anionic Kreb type polyoxometalates, K-10[Bi2W20CO2O70(H2O)(6)]nH(2)O, K-10[Sb2W20Co2O70(H2O)(6)]nH(2)O and K-8(Sb2W20Cu2O70(H2O)(6)]nH(2)O, and cationic Poly(ethyleneimine) (PEI) capped silver nanoparticles have been constructed through the layer-by-layer (LBL) technique onto carbon electrode surfaces. The cyclic voltammograms recorded during film construction exhibited redox activity associated with the Ag nanoparticles and each POM's tungsten-oxo four electron redox process. The modified electrodes were then investigated for their stability towards redox cycling at pH 2.5, thin layer behaviour and pH dependent redox chemistry. Electrochemical impedance spectroscopy was employed for the modified electrode system showing the relatively low charge transfer resistance (R-CT) of the POM based films.