The present invention provides compositions useful as a barrier layer in, for example, packaging products. The compositions generally comprise a blend of (i) a polyester resin, preferably an aromatic polyester resin such as polyethylene terephthalate (PET) and (ii) a polyamide material (e.g., MXD6). The blend optionally may further comprise (iii) an oxygen scavenging material. The present invention also provides containers (e.g., containers formed by expansion of preforms) having a multilayered body-forming portion including: a core layer comprising the aforementioned blend; and inner and outer layers of a formable polymer composition. The present invention also provides methods of making such containers.