Nafion-carbon nanotubes-viologen composites have been immobilized on glass carbon electrode surfaces. The mixtures of Nafion-carbon nanotubes could largely stabilize the viologen-modified films due to their strong adhesion on the electrode surface and the intermolecular electrostatic interaction between Nation (carbon nanotubes) and viologens. Voltammetric measurements revealed well reversible redox couples corresponding to the viologen groups. The potential differences DeltaEp and the product of De(1/2)C were closely dependant on the substituent groups of the viologens co-assembled.