Polymer particles with controlled morphologies and having diameters from about 1-20 mu can be prepared using a new suspension polymerization-based procedure. In contrast to existing procedures using emulsion polymerization, this process allows efficient preparation of supermicron particles that can be easily isolated as a dry powder. Control of the particle morphology is obtained by manipulating the monomer conversion at the beginning of the second stage of the reaction (when the second monomer is added). Two systems are studied. The first system uses styrene added to a partially polymerized MMA host particle, whereas the second system uses styrene added to a partially polymerized 45 wt % styrene to 55 wt % butyl methacrylate host particle.