This invention relates to articles made of polyester, preferably polyethylene terephthalate (PET), having coated directly to at least one of the surfaces thereof one or more layers of thermoplastic material with good gas-barrier characteristics, and novel methods of making such articles. Preferably the barrier-coated articles take the form of preforms coated by at least one layer of barrier material and the containers blow-molded therefrom. Such barrier-coated containers are preferably of the type to hold beverages such as soft drinks, beer or juice. The preferred barrier materials have a lower permeability to oxygen and carbon dioxide than PET as well as key physical properties similar to PET. The materials and methods provide that the barrier layers have good adherence to PET, even during and after the blow molding process to form containers from preforms. Preferred barrier coating materials include poly(hydroxyamino ethers). In one preferred method, preforms are injection molded then barrier-coated immediately thereafter.