AbstractMetal/metaloxide based composite materials have wide spread applications in electrochemical sensors and fuel cell applications. Hence, the present work is directed towards the fabrication of cost effective and highly sensitive electrode material for cysteine sensing. In this work, Co‐Gd2O3 nanocomposite is prepared by a simple electrodeposition route and used as electrochemical sensor material. The prepared nanocomposite materials are characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X‐ray Diffraction spectroscopy (XRD), Energy dispersive X‐ray spectroscopy (EDX), and X‐ray Photo electron spectroscopy (XPS). SEM images exhibited as hierarchical nanoflakes with open porous structure. EDX analysis showed the presence of cobalt and gadolinium. The reflections at 2θ=330 and 35.70 corresponds to the cubic structured Gd2O3 nanoparticles validated the formation of nanocomposite. Electrooxidation of L‐cysteine on Co and Co‐Gd2O3 was carried out using cyclic voltammetry technique. Upon addition of certain concentration of cysteine, the anodic peak current get increased with the simultaneous decline in the cathodic peak currents displayed the excellent electrocatalytic activity of Co‐Gd2O3 nanocomposite. The chronoamperometric experiments were performed to derive the analytical parameters like sensitivity, limit of detection and linear range. The reproducibility, stability and real sample analysis was studied using chronoamperometry.