A novel electrochemical sensor for the detection of hydrogen peroxide (H2O2) was proposed based on immobilizing Copper oxide nanoparticles (nano-CuO) on Nafion (Nf) membrane coated Pt electrode. Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to confirm the successful stepwise assembly procedure of the sensor. The electrocatalytical behaviors of the sensor were also investigated by CV and Chronoamperometry. Tests showed that nano-CuO exhibited a remarkable electrocatalytic activity for the reduction of H2O2. Under optimal conditions, the electrocatalytic response of the sensor was proportional to the H2O2 concentration in the range of 0.15 mu M-9.00 mM with a detection limit down to 0.06 mu M at 3 sigma, and achieved 95% of the steady-state current in 5 s. The low detection limit, wide linear range and high sensitivity of the sensor make it valuable for further application. (c) 2007 Published by Elsevier B.V.