A composition having gas-barrier properties, which can produce a resin film having gas-barrier properties under high humidity conditions and high abrasion resistance, and a coating film formed by thermally treating a film-like product of the composition having gas-barrier properties and a method for producing the same are provided. A composition having gas-barrier properties, comprising a water-soluble polymer having hydroxyl group (A), a water-soluble polymer having carboxyl group (B), a metal alkoxide and/or a hydrolysis condensate thereof (C), and an esterification catalyst (E), such that the weight ratio of the component (A) and the component (B) is 97/3 to 3/97, and the component (C) is contained in an amount ranging from 1 part by weight to 400 parts by weight, while the component (E) is contained in an amount ranging from 0.01 part by weight to 100 parts by weight, relative to 100 parts by weight of a mixture of the component (A) and the component (B); and a coating film obtained by thermally treating a film-like product of the composition having gas-barrier properties.