A primer coated, oriented polyester film material is provided wherein the primer is applied in an aqueous medium comprising a water dispersible copolyester consisting essentially of the condensation product of components A, B, C, and D or their polyester forming equivalents as follows:(A) about 60 to 75 mole percent of terephthalic acid;(B) about 15 to 25 mole percent of at least one dicarboxylic acid of the formula HOOC(CH.sub.2).sub.n COOH, wherein n ranges from about 1-11;(C) greater than from about 6 up to about 15 mole percent of at least one sulfomonomer containing an alkali metal sulfonate group attached to a dicarboxylic aromatic nucleus, and(D) Stoichiometric quantities, i.e., about 100 mole percent of at least one aliphatic or cycloaliphatic alkylene glycol copolymerizable therewith having about from 2 to 11 carbon atoms.The copolyester priming layer may be applied to the polyester film at any suitable stage during manufacture of the film, i.e., before or during the stretching operations. The resultant primed polyester film is found to provide excellent adhesion to many aqueous or organic solvent based coatings subsequently applied thereto.