The possibility to increase the corrosion stability of steel 45 by its anodic electrothermochemical oxidation in aqueous solutions of ammonium acetate (10–15%) is shown. Tests of oxidized samples in a sulfuric acid solution (0.5 M) allowed finding a shift of their potential to the positive range (up to 0.3 V) with respect to the platinized electrode, which was accompanied by a decrease in the conductivity of the oxide layer. The minimum corrosion rate [0.7 g/(m2 day)] in the 5% NaCl solution was obtained for the specimen oxidized at a voltage of 200 V.