Abstract: High quality, aqueous-based, heat-curable, primer coating compositions substantially free of organic solvents are disclosed. Said primer compositions include (a) from about 30% to about 75% by weight of a resinous binder which is a mixture of (i) from about 10% to about 60% by weight of finely divided epoxy resin, including blends thereof, having a weight average molecular weight of from about 900 to about 8000 and an epoxide equivalent weight of from about 450 to about 4000, and (ii) from about 5% to about 30% by weight of dispersible, methylated methoxymethyl urea resin which is a crosslinking agent having a formaldehyde:urea molar ratio of 2.2-2.8:1, methanol:urea molar ratio of 1.3-2.0:1, and toluene tolerance of at least 50 weight percent, (b) from about 25% to about 70% by weight of water, and, if desired, (c) up to about 30% by weight of pigment, including a combination of pigments.