Miscible blends of (1) a thermoplastic methylol polyester having backbone repeating units containing pendent hydroxyl and methylol moieties and divalent organic moieties such as 1,3-phenylene, 1,4-phenylene, 2,6-naphthalene, biphenylene and isopropylidene diphenylene, and (2) a linear, saturated polyester or copolyester of aromatic dicarboxylic acids, such as poly(ethylene-co-1,4-cyclohexanedimethylene terephthalate) (PETG) and poly(ethylene terephthalate) (PET), have improved clarity and exhibit enhanced barrier to oxygen relative to PET and PETG.