Self-organized nanoporous tin oxide films were fabricated by anodizing a tin substrate in an aqueous electrolyte containing oxalic or phosphoric acid. The films were characterized using FE-SEM, XRD, XPS, and TGA. In addition, the supercapacitive properties of the porous oxide films were measured using cyclic voltammetry and galvanostatic charge/discharge technique. The film demonstrated a maximum specific capacitance of 274 F g⁻¹ with long life in electrochemical charge/discharge cycles.