Cobalt sulfide (CoS) and graphene nanocomposites were prepared from cobalt nitrate, thioacetamide, and graphene as starting materials in the presence of poly(vinylpyrrolidone) as surfactant. Furthermore, its morphology and properties were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope, diffusive reflectance ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and electrochemical measurements. The XRD reveals the amorphous nature of the nanocomposites. The as-prepared nanocomposites were tested for its supercapacitance property by cyclic voltammetric (CV) experiment in 6M KOH electrolyte. CV was performed at a potential range of 0 to-0.8 V at different scan rates, and results show an excellent capacitive behavior of the nanocomposites. A maximum specific capacitance of 2423.3 F/g was obtained at a scan rate of 5 mV/s. © 2013 IEEE.