The objective of this research was to study the properties of a graphene and the possibilities of its usage it as an active material in a supercapatitor. The first step of this research was the reduction of graphene oxide (GO) to graphene (rGO)s which was carried out using NaBH4 and at pH=8 at 80°C. The obtained rGO was dropcasted on a glassy carbon support (Electrode11 and Electrode12) and then the capacitive properties of the electrodes were studied by applying cyclic voltammetry method in 0,5 mol dm-3 Na2SO4 solution. The values of specific capacitance for the Electrode11 and Electrode12 are 17.56 F g-1 and 13.9 F g-1, respectively. Apart from the samples synthesized prepared in the laboratory, a sample of commercially available graphene was also tested. The purchased sample shows higher value of the specific capacitance, equal to 64.48 F g-1. Lower capacitance values obtained for the prepared rGO are the result of a lower reduction degree of graphene sample. The Supercapacitor1 (prepared rGO) and the Supercapacitor2 (purchased rGO) are assembled using rGO samples on the glassy carbon support. A cellulose separator soaked in a solution 0,5 mol dm-3 Na2SO4 is placed between the electrodes. The testing of the supercapacitors was conducted by the cyclic voltammetry and chronopotentiometry methods. The specific capacitance of the Supercapacitor1 obtained by cyclic voltammetry method was 3.49 F g-1, while the specific capacitance of the Supercapacitor2 was 6.45 F g-1. Besides the specific capacitance value, the values of the specific power and energy were also determined by chronopotentiometry method. For the Supercapacitor1 the values of the obtained specific capacitance, energy and power are 3.323 F g-1, 2.393 W s g-1 and 0.12 W g-1, respectively. Whereas the obtained specific capacitance, energy and power for the Supercapacitor2 are 18.81 F g-1, 13.54 W s g-1 and 0.12 W g-1, respectively. Since the Supercapacitor2 has greater specific capacitance and energy, it follows that the Supercapacitor2 shows better properties than the Supercapacitor1. However, much worse stability with the increasing number of charge/discharge cycles was obtained for Supercapacitor2 which is probably due to the poor performance of the supercapacitor.