A method for treating a chromium-plated surface is provided characterized by the fact that a chromium-plated article is dipped as the cathode in a water-soluble or water-dispersible resin solution or dispersion prepared by diluting with water a resin salt of at least one synthetic polyamino resin with a water-soluble organic acid and/or a water-soluble inorganic acid, and then passing a direct current in the range of 10 - 300 volts through the aqueous bath so that there is formed a resin film on the chromium plated surface the chromium-plated surface is pretreated prior to the resin coating step by anodization in aqueous chromate solution or by heat treatment so that the surface electrode potential is greater than -0.42 volts.