Heat cured coatings cathodically electrodeposited from an aqueous dispersion of (a) an ionized reaction product of an epoxy resin and a monoamino alcohol or phenol, said reaction product also having a pendant hydrocarbon group, (b) an acid-functional aminoplast resin, and (c) a water soluble acid solubilizer, where the dispersion is free from water soluble acid which will be retained in the heat cured resinous coating are found to provide exceptional resistance to corrosion of ferrous metal substrates upon exposure to salt spray or detergent solutions.