The electrochemical preparation of barium perchlorate, Ba(ClO4)(2), from barium chlorate employing a platinum anode and a rotating stainless steel cathode is described. The effect of electrolyte concentration, cathode and anode current densities, pH and temperature of the electrolyte, and cathode rotation on current efficiency for the preparation of barium perchlorate was studied. A maximum current efficiency of 40% was achieved corresponding to an energy consumption of 5.5 kW center dot h center dot kg(-1).