Abstract: Disclosed herein is a waterproof admixture composition for concrete which is added to fabricate concrete having excellent anti-corrosive performance. The waterproof admixture composition can protect reinforcing steel bars against oxidation in the presence of salt, thereby ensuring excellent anti-corrosive performance and thus greatly improving the durability of reinforced concrete even in salt-damaged areas and corrosive environments and the like by inhibiting the corrosion of the reinforced concrete. The waterproof admixture composition comprises fly ash and silica fume as artificial pozzolan activators, a redispersible powders resin, a higher fatty acid-based metal salt and a high performance water-reducing agent wherein the composition further comprises 18 to 34% by weight of an inorganic salt and 1 to 5% by weight of tannin as an antioxidant, based on the total weight of the composition.