A gold (Au) electrode was modified with (3-mercaptopropyl) trimethoxysilane (MPS) by self-assembly method and palladium (Pd) was electrochemically in situ incorporated on it towards achieve the electrocatalytic reduction of chemical warfare agent sulfur mustard (SM) at room temperature. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) revealed the presence of Pd in the self-assembled layer of MPS. The present modification indicated one electron involvement in the electrocatalytic reduction of SM in addition to it is an irreversible adsorption controlled process. A linear response in the reduction current for SM was obtained in the range between 0.638 × 10-4 M and 0.382 × 10-3 M with a LOD and LOQ value of 0.191 × 10-4 M and 0.638 × 10-4 M, respectively. Moreover, electrochemical parameters such as diffusion coefficient (8.31 × 10-4 cm2 s-1), heterogeneous rate constant (0.461 s-1), transfer coefficient (0.54), and the number of electron involved (1.0) in the SM reduction were deduced from cyclic voltammetry results of the modified electrode. The modified electrode showed good sensitivity, stability and reproducibility. © 2011 Elsevier B.V. All rights reserved.