The reductive desorption of 2-aminoethanethiol (AET) monolayers formed on a polycrystalline gold electrode has been studied using cyclic voltammetry. Three cathodic peaks were observed and they were assigned to reductive desorption from each small domain of Au(111), (100), and (110) over the polycrystalline surface. The kinetics of adsorption were likely under the condition where the kinetic control and the diffusion control were balanced over the concentration range 5–50 μM (M = mol dm−3), whereas it was described by the kinetic control model at 100 μM. The thermodynamics of adsorption was well-described by the Langmuir isotherm. The saturation surface coverage was found to be 5.3 × 10−10 mol cm−2, which suggested that AET adsorbed lying flat on a polycrystalline gold electrode.