A two-step polymerization process was proposed to obtain composite latices with an average size ranging from submicrons to 1 μm. Negatively charged PMMA Seed latex particles were prepared by using anionic sodium lauryl sulfate (SLS), and ammonium persulfate (APS). After the removal of unreacted monomer and initiator by dialysis, seeded emulsion polymerization was carried out by swelling the PMMA seeds with monomers consisting of hydrophilic dimethyl aminoethyl methacrylate (DMAEMA) and hydrophobic styrene. A cationic initiator, 2,2'-azobis(2-amidinopropane).2HCl (V-50), was used. A small amount of non-ionic polyoxyethylene (23) nonylphenyl ether (POE23) solution was added. The weight percent of DMAEMA in co-monomer, weight ratio of monomer to polymer (M/P), and pH of the latex were changed to obtain controlled coagulation and further growth of the seed particles. Incorporation of DMAEMA was investigated by TEM observation of the particles stained with iodomethane, and by measuring the rate of quarternization of DMAEMA when iodomethane gradually diffused into the particles from the continuous phase. A maximum growth of the particles, from the initial average diameter of 0.21 μm to a final 0.56 μm, was attained when pH was set at 10.0 with a lower POE23 concentration. The final particles were stable aggregates of the several seed particles with DMAEMA incorporated between the coagulated seeds as well as deposited on the surface of the particles. The nucleation of DMAEMA-rich secondary particles was enhanced when the pH was set at 9.0. Decreasing the amount of POE23 normally promoted the growth unless the stability of the latex was affected.