TiO2 nanoparticles were prepared from TiCl4 as a precursor with ethanol solution with 1:10 ratio in ambient atmosphere, without additive. Sol-gel synthesized has been dried and calcined at (550-600)C. The structure, morphology and the particle size of the nanoparticles were investigated by X-ray Diffraction and Scanning Electron Microscopy (SEM). The optical properties were studied by UV-Visible Spectrophotometer. Results showed that the anatase phase was only in titanium dioxide powder up to 500. The average grain size of TiO2 nanoparticles was obtained in the range of (3- 30) nm. The synthesized TiO2 nanoparticles in 10-5 and 10-3 concentrations exhibited superior antibacterial activity with two types of bacteria, Escherichia coli (E-coli) and Staphylococcus aurous respectively. TiO2 nanoparticles are more efficient as antibacterial agents with Staphylococcus aurous as compared with E-coli.