Suspension polymerizations for ethylene glycol dimethacrylate (EGDM)/toluene droplets dissolving styrene-methyl methacrylate copolymers with different compositions were carried out. Hollow particles were obtained independent of the copolymer composition. In suspension copolymerizations for EGDM/divinyl benzene/toluene droplets dissolving poly(methyl methacrylate), hollow particles were produced at high EGDM content, but not at low EGDM content. Preferential adsorption of the polymer formed by the suspension polymerizations at the interfaces of the droplets over the (co)polymers preliminarily dissolved therein was one of the key factors for the formation of the hollow structure.