tThis paper reports a novel, simple and sensitive electrochemical method for the determination of formes-tane (FMT) in aqueous media (BR buffer solution, pH 5.2) on indium oxide nanoparticles modifiedcarbon paste electrode (In2O3NPs/CPE). The prepared In2O3nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fabricated In2O3NPs/CPE displayedhigh effective surface area, more reactive sites and excellent electrochemical catalytic activity towardthe oxidation of FMT. The voltammetric oxidation of FMT was studied at a carbon paste and indium oxidenanoparticles modified carbon paste electrodes by cyclic voltammetry and its determination was carriedout by square wave anodic adsorptive stripping voltammetry (SWAASV). The electrochemical parame-ters such as surface concentration ( ), electron transfer coefficient (˛), and the electron transfer rateconstant (ks) of FMT at the modified electrode were calculated. Under the optimal conditions at In2O3NPs/CPE, a linear relationship was realized between the anodic peak currents and FMT concentrations inthe range of 0.19–2.91 M, with the detection limit of 6.2 × 10−8M. This modified electrode was used asa sensor for determination of FMT in blood serum and urine samples with satisfactory results.