An aqueous dispersion of improved stability, said dispersion consisting essentially of a mixture of

(A) 10 to 90% by weight of an ethytene/α,β-unsaturated carboxylic acid copolymer containing 12 to 20% by weight on an average of α,β-unsaturated carboxylic acid units or the metal salt thereof, and
(B) 90 to 10% by weight of an ethylene/α,β-unsaturated carboxylic acid copolymer containing 5 to 12% by weight on an average of α,β-unsaturated carboxylic acid units or the metal salt thereof,

said mixture containing 8 to 20% by weight on an average, based on the weight of the mixture, of the α,β-unsaturated carboxylic acid units, 30 to 80% of which units are present in the form of metal salts, and said mixture not containing more than 5% by weight, based on the weight of the mixture, of a fraction of the ethylene/a,/3-unsaturated carboxylic acid copolymer having an α,β-unsaturated carboxylic acid unit content of less than 5% by weight or its salt, and more than 10% by weight, based on the weight of the mixture, of a fraction of the ethylene/α,β-unsaturated carboxylic acid copolymer having an α,β-unsaturated carboxylic acid unit content of more than 20% by weight or its salt.