Monodisperse poly(styrene-co-divinylbenzene) microspheres crosslinked with different concentrations of divinylbenzene were synthesized by two-stage dispersion polymerization in ethanol dispersion medium with poly(N-vinyl pyrrolidone) as a stabilizer and 2,2'-azobisiso-butyronitrile as a radical initiator. The microsphere size, size distribution, surface morphology, and structure were characterized by a particle analyzer, a scanning microscope and IR spectroscopy. The effect of the adding time, the adding rate, and the concentration of crosslinker on the size, size distribution, and shape of the resulting particles were also investigated. Highly crosslinked monodisperse microspheres with diameters from 2 to 4 pm were obtained. The SEM characterization showed that the resulting microspheres had spherical shapes with smooth surfaces. The obtained microspheres have good resistance to solvent whether at ambient or heating temperatures and are thermally stable. (c) 2008 Wiley Periodicals, Inc.