The present invention provides a resin composition which comprises EVOH and a thermoplastic resin other than EVOH and which generates less odor and therefore is suitable for food packaging applications. The invention also provides an environmentally friendly method for producing a resin composition, without releasing any carboxylic acid such as acetic acid to the peripheral environment. A resin composition containing less carboxylate group is obtained by contacting an ethylene-vinyl alcohol copolymer resin with an aqueous solution containing both carbon dioxide gas and at least one additive selected from the group consisting of an alkali metal salt (A) and a boron compound (B) and then melt kneading with a thermoplastic resin (G) other than EVOH.