Abstract: A process of preparing aqueous dispersions of multi-component film-forming polymer particles, suitable for use in a cathodic electrodeposition process. The disperse particles, which may be thermoplastic or thermosetting, are derived from mixtures of pre-formed polymer and addition polymer formed in situ. The process is carried out at a pH below 10 and in the presence of a selected cationic surface active agent which stabilizes the dispersion below pH 10 but renders it unstable at a pH of 10-11.