A nonenzymatic glucose sensor prepared from a mixture of ruthenium oxide (RuO2) and graphene (GR) sheet as a composite paste electrode (RuO2/GR CPE) was developed. The surface morphology and microstructure of the RuO2/GR CPE were studied by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analyses. The RuO2/GR CPE was characterized by cyclic voltammetry, amperometry and electrochemical impedance spectroscopy. The RuO2/GR CPE displayed a synergism between RuO2 and GR in during the electrocatalytic oxidation of glucose in 3 M NaOH. The formations of Ru(VI)/Ru(IV) and Ru(VII)/Ru(VI) redox couples and the remarkable physical properties of GR were the reasons behind this phenomenon. The RuO2/GR CPE had a linear response toward glucose over a concentration range of 0.1 to 22 mM with a detection limit of 5.60 ± 0.03 µM (S/N = 3) and a sensitivity of 78.4 μA mM−1 cm−2. The sensor showed good stability and reproducibility.The RuO2/GR CPE was not affected by the traditional interferents of the glucose sensor, namely, ascorbic acid and uric acid.