Synthesis of monodispersed NiFe2O4 nanospheres by a simple method was reported. Structure, morphology and characterization of the nanospheres were performed using field emission scanning electron microscopy, X-ray diffraction and FTIR spectroscopy. Electrochemical properties of the prepared nano-spheres were studied in order to realize their suitability and susceptibility as an electrode material for supercapacitor applications. NiFe2O4 nanospheres showed a high specific capacitance of 122 F g−1 and a great specific energy of 16.9 Wh kg−1 at a high current density of 8.0 A g−1. The maximum specific capacity of the nanospheres was even more, which can reach 137.2 F g−1 at 4 A g−1 of current density. The results showed an excellent long-term cycling stability for the NiFe2O4 nanospheres-based electrodes. The capacitance did not decrease, compared to the initial value during 100 galvanostatic charge-discharge cycles.