SiO2/polystyrene nanocomposite particles were synthesized via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as surfactant and hexadecane as hydrophobe in the presence of silica particles coated with methacryloxy(propyl)trimethoxysilane (MPS) surface coupling agent. The silica particles were individually coated with polymer yielding a very homogenous nanocomposite latex which was very stable in a wide range of ionic strengths. Monomer conversion was reasonably high and fast.