Abstract: Nanosilica (nS) are synthesized using the sol-gel method, with tetraethylorthosilicate (TEOS) as precursors, ammonia (NH3) as base catalysts, water as hydrolysis and ethanol as solvents. Polyvinyl alcohol is added to the sol solution, serving as a capping agent. The purpose of this research is to know functional group, from TEOS with the addition of variation of PVA concentration and without addition of variation of PVA concentration. Functional groups were analyzed using Fourier Transform Infra Red (FTIR). The nanosilicas of the TEOS precursors using the sol-gel method were successfully synthesized by marked detection of typical peaks of SiO2 in all samples of Si-O-Si (siloxane) and Si-O Keywords: nanosilica, TEOS, PVA, sol-gel method