Abstract: Hierarchical porous activated carbon (AC) was obtained by the carbonization of dried spinach leaves followed by acti-vation with KOH. The product was characterized by nitrogen adsorption, FT-IR, FE-SEM and electrochemical tests. The AC has a dominant number of micropores, a medium number of mesopores and a few macropores with a specific surface area up to 2616 m ² / g and a large number of oxygen-containing functional groups. The AC electrode exhibits a good double-layer capacitive behavior with a specific capacitance of 238 F/ g in a 2 mol/ L KOH electrolyte. A supercapacitor made of the AC has a high energy density of 10. 1 Wh/ Kg at a current density of 0. 5A/ g and an excellent cyclic stability for 2000 cycles over a potential range from 0 to 1. 2V.