The two-electron two-proton redox reaction of the benzoquinone-hydroquinone (Q/QH 2) couple in aqueous solution has been studied by cyclic voltammetry at platinum electrodes coated with polypyrrole benzensulphonate. In contrast to the behaviour on bare platinum, the voltammetric response of the Q/QH 2 couple on polypyrrole is close to the Nernstian behaviour within pH range from 1 to 7. The heterogeneous rate constant k s determined from the peak separations is in the range of 10 −3 cm s −1. It is independent of the film thickness in a wide range and slightly pH-dependent, with a minimum at pH 4. Compared with related results based on polypyrrole perchlorate-coated gold electrodes, less aging of the catalytic efficiency is observed. Higher peak currents with increasing polypyrrole coverage suggest partial diffusion of the substrate into the bulk of the film. Preliminary studies on more complex quinones, ubiquinone-1, plastoquinone-1 and the bis-quinone of dibenzo [18] crown-6 demonstrate similar catalytic effects of polypyrrole layers. Potential applications of polypyrrole-coated electrodes in organic electrochemistry and bioelectroanalytical chemistry are discussed.