The electrochemical reduction behavior of a series of aromatic oxime derivatives was characterized by voltammetry on a mercury electrode. Oxime compounds have both carbonyl and amino groups next to the functional oxime group and carry different substituent groups on the benzene side ring. Square wave voltammetry and differential pulse voltammetry revealed a strong pH dependency of the reduction peak potential and currents, while cyclic voltammetry revealed an irreversible nature of the electrode reaction. Substituent effects on the reduction of substances were closely related to their molecular structures estimated by theoretical Hartree-Fock calculations. The structure-reduction potential and pK(a)-substituent relationships are discussed. (C) 2016 The Electrochemical Society. All rights reserved.