Undercoating composition for polyesters containing epoxy compounds

An undercoating composition for photographic polyester film wherein the polyester is a condensation product of a dibasic aromatic acid and a glycol which contains (1) a compound having two or more epoxy groups in its molecule and a molecular weight of about 1,000 or less, said compound being represented by general formula (I):

• ##STR2## wherein R.sub.1 to R.sub.5, which may be the same or different, represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n represents an integer of 2 to 6 and A represents a linear or cyclic group having n nitrogen atoms or n oxygen atoms where the nitrogen atoms or oxygen atoms are directly bonded to the glycidyl group, a 5- or 6-membered heterocyclic ring having two or more active nitrogen atoms in the ring, a nitrogen atom, a phosphate group or a sulfate group;
• and (2) water as a primary solvent or sole solvent.