Via the green chemistry route, Mn3O4/amorphous carbon nanoparticles have been synthesized. Dextrose was used as the reducing agent, and starch was used as the capping agent. The X-ray diffraction patterns reveal the Hausmannite tetragonal structure of the synthesized Mn3O4 particles. EDAX analysis confirms the presence of carbon and stoichiometry of Mn3O4. Morphological studies reveal the nanospherical nature of the synthesized particles. The FTIR spectra confirm the presence of Mn-O bonds. Mn3O4/AC 500 exhibits highest specific capacitance of 522 F g(-1) at a specific current of 1 A g(-1), when measured from the charge-discharge process. This value is superior to previous reports on Mn3O4 nanoparticles as an electrode for supercapacitors. Higher energy density of 58.72 W h kg(-1) could be observed for Mn3O4/AC 500, which is higher than lead acid batteries and comparable to those for the nickel hydride batteries. These results indicate that Mn3O4/AC 500 is a promising electrode for supercapacitor applications.