The stability of the unreconstructed Au(100) surface against potential-induced reconstruction, which occurs at negative potentials, has been investigated in sulfate solutions. It will be shown that electrochemical annealing of Au(100)-(1 x 1) in a chloride-containing solution slows down the (1 x 1) -,(hex) transition to Such an extent that experiments with the unreconstructed Au(100) electrode become feasible over a wide potential range. Electrochemical annealing removes surface defects which otherwise would act as nucleation centers for the potential-induced reconstruction.