A series of magnetic poly(methyl methacrylate) (PMMA) particles were synthesized by a suspension polymerization technique. Poly(vinyl alcohol) (PVA 1788) and magnesium carbonate were used as stabilizer and acid stabilizer, respectively, while Fe3O4 magnetic fluid and ethylene glycol dimethacrylate were as magnetite and crosslinking reagents. All the particles have diameters ranging from 1 to 3 mm, while the particle size and its distribution could be adjusted by selecting a suitable polymerization medium. The effect of reaction parameters such as quantity of NaCl, magnesium carbonate and crosslinking reagent, water-to-monomer ratio and polymerization temperature on particle sizes was investigated in detail. The iron content of the composite particles was determined by using an atomic absorption spectrometer, and a vibrating sample magnetometer (VSM) clearly showed that the magnetic PMMA particles were superparamagnetic.