An improved nonenzymatic glucose sensor based on copper oxide-doped nickel oxide composite microfibers (CuO-NiO-MFs) modified fluorine tin oxide (FTO) electrode was prepared by electrospinning and calcination technologies without using any immobilization. The results of cyclic voltammetry (CV) and chronoamperometry demonstrated that the CuO-NiO-MFs modified electrode displayed much higher electrocatalytic activity than the nickel oxide microfibers (NiO-MFs) modified electrode toward glucose. The nonenzymatic glucose sensor based on CuO-NiO-MFs showed the highest sensitivity of 3165.53 mu A mM(-1) cm(-2) with the lowest detection limit of 1 x 10(-9) M (signal/noise ratio (S/N) = 3) in the nonenzymatic glucose sensors that have been reported in the literature. Additionally, its application for detecting glucose concentration of human serum sample showed good agreement with the results obtained from automatic biochemical analyzer. (C) 2011 Elsevier B.V. All rights reserved.