The voltammetric behavior of polyuridylic acid + mercuric acetate solutions at banging mercury drop electrodes has been studied in neutral aqueous solution. Adsorbed polyuridylic acid(poly(U)) efficiently accumulates mercury, resulting in a peak voltammogram at: ca. -0.6 V vs. SCE for the reduction of Hg(II) coordinated to the poly(U) film. The size of this wave was markedly dependent on the accumulation time.:The magnitude of the charge associated with the peak voltammogram indicated formation of multilayer poly(U)-Hg(II) electroactive films. This voltammetric current could be distinguished from the reduction of covalent carbon-mercury bonds in mercurated poly(U), poly(U-Hg), prepared by treating the former with mercury(II)acetate at elevated temperature. Analysis of the surface voltammetry of poly(U-Hg) gave an estimate of the extent of mercuration.