The polypyrrole/carbon foam composite electrodes for electrochemical capacitors were fabricated by electrochemical polymerization of pyrrole in aqueous solution on the carbon foam, which prepared by carbonization of polyacrylonitrile membranes supported by carbon papers. The carbon foams were characterized with FTIR, SEM and the Brunauer-Emmett-Teller technique. The electrical capacitance of the composite electrodes was investigated with cyclic voltammetry (CV). The prototypes of electrochemical capacitors composed with polypyrrole/carbon foam electrodes were tested with ac impedance spectroscopy and chronopotentiometry technique. The dependence of specific power and specific energy on conditions of electrochemical polymerization of pyrrole was studied. Based on total weight of the electrodes in a prototype electrochemical capacitor, energy density could reach 2.5 Wh/kg. All results showed that polypyrrole/carbon foam composite materials had good potential applications in electrochemical capacitors. (C) 2003 Elsevier B.V. All rights reserved.