Chemical functionalization on nano-scaled silica particles was performed through the reaction between the silanol group of silica and the oxirane ring of epoxy compounds. The occurrence of the surface functionalization and the chemical structures of the resulting products were characterized with FTIR and 1H NMR. Energy dispersive x-ray spectrometry and transmission electronic micrography observation on the silica particles also confirmed the surface functionalization. This approach provides another method to organically functionalize nano-scaled silica particles and can be applied to the preparation of organic–inorganic nanocomposites. ; JNL0002918