Background: Radioactive yttrium glass microspheres are used for liver cancer treatment. These yttrium aluminum silicate microspheres are synthesized from yttrium, aluminum and silicone oxides by melting. There are two known processes used to transform irregular shaped glass particles into microspheres, these ‘spheroidization by flame’ and ‘spheroidization by gravitational fall in a tubular furnace’. Materials and Methods: Yttrium aluminum silicate microspheres with the approximate size of 20-50 µm were obtained when an aqueous solution of YCl3 and AlCl3 was added to tetraethyl orthosilicate (TEOS) and pumped in to silicone oil and stirred constantly the temperature of 80˚C. The resulting spherical shapes were then investigated for crystallization, chemical bonds, composition and distribution of elements by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), carbon/sulfur analysis, X-ray photoelectron spectroscopy (XPS) and SEM/EDS analysis. Results: The particles produced by the above-mentioned method were regular and nearly spherical in shape. The results of topographical analysis of a cross-section showed that form of the microspheres had formed a ‘boiled egg’ structure. This method has an advantage over other methods in that the process does not require high temperatures. Conclusion: This paper reports on a novel method to produce yttrium glass microspheres. The resulting microspheres were formed with a silicon crust so the proposed method is expected to be suitable for application in the production of radioactive seed sources for implantation in tumors and cancer tissue.