Anhydrous mesoporous ruthenium oxide was synthesized by a simple non-ionic surfactant templating method using Pluronic 123 and tested as an active electrode material for an electrochemical supercapacitor. XRD studies showed the fort-nation of the anhydrous phase of RuO2 for the material calcined at 400 degreesC/5 h. Cyclic voltammetric studies were performed to estimate the capacitance of the synthesized material. There has been a strong, dependence of the capacitance of the material on the voltage scan rates. The capacitance values showed a linear decrease with respect to the increase in the scan rate. The origin of capacitance was found to be from the pseudocapacitance in the RuO2 material and not from any double layer contribution as evidenced by the cyclic voltammetry (CV) studies at different molar concentrations of the electrolyte. The capacitance for anhydrous RuO2 was found to be 58 F/g. The synthesis, structural and electrochemical properties of the mesoporous RuO2 are discussed in detail. (C) 2004 Elsevier B.V. All rights reserved.