The electrodeposition of aluminum at glassy carbon, platinum, and tungsten electrodes in slightly acidic chloroaluminate melts has been studied using cyclic voltammetry, chronopotentiometry, chronoamperometry, and related techniques. The reduction of ions involves a nucleation process at glassy carbon electrodes and to a lesser extent, at the platinum and tungsten electrodes. At platinum electrodes alloy formation is also involved. The discrepancies in the values of diffusion coefficients obtained by three different methods may be attributed to the nucleation effect.