The electrochemical behaviour of the Zn(II)-Zn(Hg) system in aqueous ethylene glycol (EG) solutions containing 5.0 × 10-2 LiClO4 has been studied by polarography and cyclic voltammetry. The reversible half-wave potentials, the diffusion coefficients and the Walden products for Zn(L[) have been polarographically determined. The standard free energies of transfer of 1 mol of Zn(II) ions from water to EG-water mixtures, AGo,b tained from the reversible half-wave potentials vs. the ferrocene electrode scale, are always negative, indicating a greater stability of Zn(II) in EG-water mixtures than in pure water. The splitting of the AGyvalues into electrostatic and chemical contributions shows that the mixtures are more basic than water. The analysis of the ΔG10 variation of the Walden product with solvent composition indicates an enhancement of the solvent structure in the water-rich region. The diffusion coefficient for Zn in mercury, the transfer coefficients for Zn(II) electroreduction, and the apparent standard rate constants of the Zn(II)-Zn(Hg) system have been determined by cyclic voltammetry. The change in the kinetics with solvent composition is discussed in terms of existing models.