Abstract: This invention relates to aqueous epoxy resin-containing compositions useful for depositing coatings on metallic substrates in order to protect substrates against corrosion. The aqueous compositions generally comprise (A) an organic resin component consisting essentially of at least one water-dispersible or emulsifiable epoxy resin; (B) a non-ionic emulsifier, (C) chromium trioxide, (D) a conductive pigment, (E) water, and, optionally, polytetrafluorethylene as a lubricant. The compositions may also contain phosphoric acid or an alkylphosphoric acid. These compositions are useful in coil coating operations to improve the electrocoatability of a metal substrate, in particular, steel, galvanized or aluminized substrates. The basecoated metal can then be conventionally coated or electro coated with weldable or non-weldable primer coatings and may be followed by the application of decorative topcoats.