This work reports on the direct electrochemistry of the Desulfovibrio gigasaldehyde oxidoreductase (DgAOR), a molybdenum enzyme of the xanthine oxidase family that contains three redox-active cofactors: two [2Fe-2S] centers and a molybdopterin cytosine dinucleotide cofactor. The voltammetric behavior of the enzyme was analyzed at gold and carbon (pyrolytic graphite and glassy carbon) elec-trodes. Two different strategies were used: one with the molecules confined to the electrode surface and a second withDgAOR in solution