We report herein the fabrication of a novel electrochemical sensor based on palladium nanoparticles immobilized on ethylenediamine cellulose which is consisted of uniformly distributed palladium nanoparticles with the main average size of 4.7-6.9 nm. The structure of the prepared nanocomposite was investigated by X-ray powder diffraction, transmission electron microscopy and thermogravimetric analysis techniques. The prepared catalyst was immobilized on the surface of glassy carbon electrode using drop casting method to fabricate an electrochemical sensor toward hydrazine. The modified electrode showed good catalytic activity for the electrooxidation of hydrazine (pH = 7.0), with a substantial decrease in anodic overpotentials (850 mV) and an increase in anodic peak current (about 4 times) in comparison with the unmodified electrode. A linear relationship was observed between the differential pulse voltammetry currents and the concentration of hydrazine within the range of 5-150 mu M with the detection limit (S/N = 3) of 1.5 mu M. The diffusion coefficient (D = 2.3 x 10(-5) cm(2) s(-1)) was calculated for hydrazine, using chronoamperometry. (C) 2012 Elsevier B.V. All rights reserved.