The present investigation is mainly on the synthesis, characterization and determination of some properties of new compound cetylpyridinium hexafluorosilicate for his potential use as caries-preventive and antibacterial agent. Hexafluorosilicate of the composition (C21H38N)2SiF6 was separated as crystalline product of interaction of hexafluorosilicic acid with the methanol solution of cetylpyridinium chloride. This complex was characterized by elemental analysis, IR, 1H and 19F NMR, mass-spectrometry, differential thermal analysis, and solubility data. The IR spectral data indicates on absence of noticeable distortion of the symmetry of SiF62– anion with regard to Oh. The studied compound is characterized by the predicted tendency to hydrolyze in dilute aqueous solutions with the formation of silica and fluoride anions.