tA novel electrochemical sensor based on the use of boron doped CeO2nanocubes modified glassy carbonmicrospheres paste electrode (B-CeO2NCs/GCPE) was prepared and applied for selective and sensitivedetermination of xanthine (XA) and hypoxanthine (HXA) individually and simultaneously. The mor-phology, composition and structural properties of the undoped and B doped CeO2nanocubes werecharacterized by X-ray diffraction, energy-dispersed X-ray spectrometry (EDS) and transmission elec-tron microscopy (TEM). Electrochemical activities and the surface analysis of the modified electrodewere investigated using scanning electron microscopy (SEM) and cyclic voltammetry (CV). From the B-CeO2NCs/GCPE, well oxidation peaks and enhanced peak currents of XA and HXA were observed owingto the excellent catalytic activity of B-CeO2NCs. For individual detection, the linear responses of XAand HXA were in the concentration range of 5.42 × 10−8–1.31 × 10−5M and 3.98 × 10−7–6.01 × 10−5Mwith detection limits of 3.02 and 6.17 nM, respectively. For simultaneous detection by synchronouschange of the concentration of XA and HXA, the linear ranges were 1.98 × 10−7–9.45 × 10−6M and3.98 × 10−7–1.28 × 10−5M with detection limits of 3.65 and 8.17 nM, respectively. The practical appli-cation of the modified electrode was demonstrated by simultaneously determining the concentrationsof XA and HXA in human biological fluids and in fish meat samples with satisfactory results.