We report the preparation and characterization of viologen-functionalized generation 2, 4, and 6 poly(amidoamine) (PAMAM) dendrimers. An amidation reaction between the succinimide ester of 1-ethyl-1 ' (3-propionic acid)-4,4 ' -bipyridylium dibromide and the dendrimer primary amines resulted in 13-34% end group functionalization. The water-soluble dendrimers were examined by H-1 NMR, MALDI-TOF MS, and UV-vis spectroscopy to determine the extent of functionalization. UV-vis spectra, obtained following chemical reduction of the viologenated dendrimers, indicated that the viologen radical cations were largely dimerized, which demonstrates the close proximity of the terminal viologens. Dynamic light scattering (DLS) measurements indicate that the oxidized viologenated-dendrimers are predominately unaggregated in aqueous electrolyte solutions. Diffusion coefficients determined by chronoamperometry for the three generations of viologenated PAMAM dendrimer are within 15% of values calculated using the Stokes-Einstein relationship for individual unaggregated dendrimers. Reversible voltammetry was obtained for all three generations of dendrimers for the first viologen reduction wave. The magnitude of the peak or steady-state currents indicated incomplete electrolysis of the dendrimer viologen moieties, whereas the presence of a single wave showed that all electrochemically addressable groups were equivalent. Cycling through the second reduction wave resulted in electrode passivation due to irreversible electroprecipitation. Adsorption of a stable film of oxidized viologenated-dendrimer on a Au electrode is also demonstrated by cyclic voltammetry.