The electrochemical preparation of magnesium perchlorate from magnesium chlorate employing a platinum anode and a rotating stainless steel cathode is described. The effect of electrolyte con,=en-tration, cathode and anode current densities, pH and temperature of the electrolyte and cathode rotation on current efficiency for the preparation of magnesium perchlorate was studied. A maximum curren t efficiency of 65-72% was achieved. Based on the results obtained on the laboratory scale, a 100A cell was designed, fabricated and operated