Pure anatase, nanosized and Sn4+ ion doped titanium dioxide (TiO2) particulates (TiO2-Sn4+) were synthesized by hydrothermal process. TiO2-Sn4+ was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn4+ doping to TiO2 against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO2-Sn4+ in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO2-Sn4+ is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO2-Sn4+ from 10 to 50% in the coating solution increased antibacterial effect. (C) 2008 Elsevier B.V. All rights reserved.