Superparamagnetic iron oxide (SPIO) incorporated polystyrene beads of uniform size distribution (approximate to 170 nm) and high magnetic content (approximate to 40%) are synthesized by emulsion styrene polymerization in the presence of functionalized SPIO. The role of surface functionality on the polymerization process and SPIO incorporation is investigated by carrying out styrene emulsion polymerizations with different functionalities on SPIO. A unique combination of oleic acid and (2-acetoacetoxy) ethyl methacrylate as surface ligands for SPIO is used to attain the best magnetic beads. (c) 2012 Wiley Periodicals, Inc.