A new siloxane polymer containing covalently attached Meldola Blue has been synthesized and shown to mediate the oxidation of the reduced nicotinamide adenine dinucleotide cofactor (NADH). Cyclic voltammetry and stationary potential experiments demonstrate that spectrographic graphite electrodes coated with this polymer can electrocatalytically regenerate NAD+at a substantially lower overvoltage (e.g., 0 mV vs. SCE) than can unmodified electrodes. These polymer-modified electrodes should be useful as transducers in dehydrogenase-based biosensors.