The polarographic behavior of the redox polymer poly-p-xylylviologen dibromide has been examined over the pH range 2.00–8.00. Two irreversible waves with half-wave potentials of −0.496 and −0.936 V vs SCE were observed. The pH dependence of the relative wave heights appears to suggest that the system conforms to a protonation equilibrium where the protonated form reduces, at the DME, at the lower negative potential and the second wave is due to the unprotonated species. Analysis of the limiting current-pH relationship for a given concentration of the compound yielded a value of 7.94 × 10−−5(μ=0.1 M) for the dissociation constant of the protonated form.