Polymeric microbeads are known as spherical particles that are 1-1,000 microns in diameter. Monodisperse polymeric particles are widely used in scientific and technological applications such as diagnosis of illness, electronics, catalyst carriers, coatings, biological sensors, etc. In general, microbeads are synthesized by using different polymerization techniques such as solvent evaporation, emulsion and dispersion polymerization. However, dispersion polymerization is one of the common techniques to synthesis monodisperse particles. In this project, polyhedral oligomeric silsesquioxanes (POSS) containing polystyrene (PS) based monodisperse microbeads were prepared by using dispersion polymerization. The function of different functional POSS nanoparticles (i.e. amino, epoxy) is to modifiy the surface properties of PS microbeads. Fourier Infrared (FTIR) Spectroscopy showed that the surface of microbeads were functionalized.X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were proved the presence of POSS particles on the surface of PS microbeads. Gel permeation chromatography (GPC) results showed that the molecular weight of PS microbeads was increased with incorporation of POSS nanoparticles. It was revealed from thermogravimetric analysis (TGA) data that percent char yields of POSS/PS microbeads are higher than that of neat PS microbeads. In addition, scanning electron microscopy (SEM) and optical microscope images were clearly exhibited the mono-sized distribution of microbeads. Keywords: Polymeric microbeads, dispersion polymerization, PS, POSS