A facile, cost effective and efficient method was developed to synthesize pure phase and controlled morphology of Fe3O4 nanoparticles. These nanoparticles are ferromagnetic in nature at room temperature. The Verwey transition, suggests that this method could be an efficient method to produce pure phase Fe3O4 nanoparticles. The electrochemical measurements indicate that Fe3O4 can be used for ultra-capacitor applications. The obtained high specific capacitance, excellent cyclic stability and ferromagnetic behavior at room temperature suggest that this facile method could be used for the production of cost effective magnetic and environment friendly iron oxide nanoparticles for next generation ultra-capacitor applications.