Abstract: Disclosed are a resin dispersion and a cationic electrodeposition coating composition including the same, in which the dried coating film of the electrodeposition paint is lead-free and has an epoxy-acrylic double-layered structure for displaying excellent properties, and in which an organic solvent content can be minimized. A resin dispersion of a cationic electrodeposition includes an aqueous dispersion prepared by the following processes. The resin dispersion includes a cationic electrodeposition resin, deionized water, an acid for neutralization, a reaction product of manganese phosphate and an acid diluted in an deionized water to 10%, and a cationic surfactant.