Sodium percarbonate (SPC) can be produced electrochemically from aqueous Na2CO3 solution in both its 2Na(2)CO(3)center dot 3H(2)O(2) and Na2C2O6 forms simultaneously. This was achieved in a two-compartment cell separated by a cation-exchange membrane. Na2C2O6 was produced on the anodic side by water oxidation on a boron-doped diamond electrode, with anodic current efficiencies of 20-40%. On the cathodic side, SPC was synthesized from carbonate through generation of H2O2 by oxygen reduction on high-surface-area carbon felt. Cathodic current efficiency was 60% and nearly constant. The effect of Na2SiO3 as a percarbonate stabilizer was studied during electrolysis and during storage, with 4 g/L giving the best performance.