This paper reports on the electrocatalytic and electroanalytical activity of metallic silver electrode (MSE) for ornidazole (ONZ) reduction using cyclic voltammetry (CV), square wave voltammetry (SWV), chronoamperometry, Tafel plots, and electrochemical impedance spectroscopy (EIS). Voltammetry results show an irreversible response with a significant shift to positive potentials. Based on the polarization curves, the Tafel slope is higher than 120 mV per decade indicating the Volmer step as rate determining step. The MSE presents the highest exchange current density (i0) value (6.452 µA/cm2), which further confirms their higher electrocatalytic activity towards ONZ reduction. Under the optimized conditions, MSE showed a good linearity in the concentration range from 8.0 × 10–7 mol L–1 to 6.0 × 10–5 mol L–1, with a detection limit (LOD) of 4.38 × 10–7 mol L–1. The MSE was successfully applied for the determination of ONZ in human blood.