Cobalt oxide (Co3O4) and zinc doped cobalt oxide (ZnCo3O4) nanoparticles were synthesized by co- precipitation method whereas ZnCo3O4/reduced graphene oxide (rGO) nanocomposite were synthesized by simple hydrothermal method. The structure of the as synthesized Co3O4, ZnCo3O4 and ZnCo3O4/rGO nanomaterials were characterized by powdered X – ray diffraction (XRD), FTIR and uv-vis spectroscopy. The electrochemical properties of the synthesized nanomaterials were investigated by employing cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The voltammograms recorded in the presence of K3Fe(CN)6 and 0.1 M KCl at ZnCo3O4/rGO/CPE results enhanced peak current and from Rundles - Sevcik plot a larger electroactive surface area 0.285 Cm2 were evaluated compared to Co3O4/CPE (0.144 cm2 ) and ZnCo3O4/CPE (0.213 cm2). Besides, EIS spectra showed a low charge transfer resistance on ZnCo3O4/rGO surface. Likewise the oxidation of 2 mM glucose in 0.2 M NaOH on the modified electrodes at various scan rate were studied using CV. The recorded voltamogram results two redox pair at all modified electrodes. It was also observed the peak current was larger at ZnCo3O4/rGO modified CPE whereas the onset and oxidation peak potentials appeared at lower values due to catalytic synergetic effect of Zn and Co3O4 nanoparticles. The detection of glucose concentration in standard (0.01 – 10 mM) as well as in real sample solutions were performed by applying amperometry methods at ZnCo3O4/rGO modified CPE. At optimized experimental conditions, applied potential (+0.5V) and 0.2 M NaOH supporting electrolyte, the sensor (ZnCo3O4/rGO/CPE) demonstrated a moderate linear range 0.01 – 10 mM , sensitivity of 64.018 μA mM-1cm-2 and lower detection limit of 5.695 µM. In addition to this, the developed sensor detected glucose in the presence of biologically interfering species and chloride ions. Furthermore, the developed method showed appreciable repeatability (RSD = 2.89%) and stability since it retains 75% of the initial response after 8 day storage. The sensor was also applied for the detection of glucose in blood sample the result was in good agreement with the concentration determined using spectrophotometric method. Therefore the developed sensor can be served as an alternative method for the electrochemical detection of glucose.