Stable miniemulsions of styrene or yl, methacrylate (MMA) were prepared in the presence of hexadecane and a styrenic polymerisable surfactant, the vinylbenzylsulfosuccinic acid sodium salt (VBSS). They were polymerised to high conversion, using potassium persulfate (KPS) or 2,2'-azoisobutyronitrile (AIBN) with no significant change in the particle size during reaction. The stability of the latexes was excellent when KPS was used, and the reasons for this are discussed. The size of the particles was further increased by using these latexes as a seed, and feeding a continuous stream of monomer in the presence of another polymerisable nonionic surfactant.