Cationic core/shell polystyrene/poly(methyl methacrylate) latexes (PS/PMMA) have been produced with a core/shell diameter ratio of 1:7.5 by starved semicontinuous emulsion polymerization. A cross-linked 80/20 PS/PMMA seed 70 nm in diameter gave 530-nm particles in three steps of PMMA growth. Dynamic light scattering and scanning electron microscopy were used to measure particle sizes. Locations of the cores in the particles were imaged by transmission electron microscopy. Growth using larger core latexes increased particle diameter to 800 nm, but second generation latex particles prevailed in attempts at further growth.