Carbon supported hydrous ruthenium oxide was prepared by ail ultrasonic threatment of carbon black-RuOxHy sol mixture (impregnation). Black Pearl 2000(R) was used as a supporting material, while an oxide sol was prepared by forced hydrolysis of hydrous RuCl3. The influence of kthe RuOxHy sol aging time and the amount of oxide solid phase in the impregnating medium oil the capacitive behavior of prepared carbon supported hydrous ruthenium oxide was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The oxide amount in the composite increases with increasing concentration of oxide particles in the impregnating medium. The composite specific capacitance decreases with increasing aging time of oxide sol, while increases with increasing concentration of oxide particles in the impregnating medium. Transition line model fits well the composite impedance behavior indicating a distinctive capacitive response of the inner and the outer composite active surface. This distinction becomes more pronounced as the amount of oxide in the composite increases.