Polymethylmethacrylate particles with narrow size distributions with different sizes in the range of 1.25-4.58 mu m were produced by dispersion polymerization of methylmethacrylate (MMA) in ethanol/water media, by using 2,2’-azobisisobutyronitrile (AIBN) (as an initiator), (PVP) poly(vinyl pyrrolidone) (as a stabilizer), and eerie ammonium nitrate (CAN) (as a coinitiator and also as a costabilizer). Particle size was increased by increasing the initiator concentration and the ethanol : water ratio, and by decreasing the monomer : dispersion medium ratio and the PVP and CAN concentrations. The addition of CAN in the recipe of the MMA polymerization improved the monodispersity, and also increased the monomer conversion rate.