Micron-size monodisperse polymer particles were prepared by dispersion copolymerization of methyl methacrylate with a hydrophilic poly(2-oxazoline) macromonomer in an aqueous methanol solution, in which the macromonomer acted as a comonomer as well as a stabilizer.A small amount of the macromonomer was sufficient to produce such polymer particles.The particle size decreased with increasing the amount of the macromonomer.From ESCA analysis of the particles, poly(2-oxazoline) chains were found to be locally present on the surface.