The reduction of indium at the dropping mercury electrode in sodium nitrate and sodium perchlorate solutions has been studied. The induction is diffusion controlled but the process is not reversible. The kinetic parameters α and k s, have been calculated by Gelling's method. The k s was found to be of the order of 1·25 × 10 −3 cm/s, showing that the reduction is a quasi-reversible process. The effect of temperature and concentration of the supporting electrolyte on kinetic parameters have been investigated. The apparent heat of activation Δ H s has been calculated. As the temperature increases or the concentration of the supporting electrolyte decreases, the reduction proceeds towards more reversible side.