Abstract: The process of Heterogeneous Photocatalysis (HP) using titanium dioxide photocatalysts is a field of immense research potential for researchers worldwide. TiO2 as a photocatalyst has been widely applied for air and water remediation. This study reports the synthesis of a visible light responsive nanosized TiO2 photocatalyst by a modified sol-gel process. The synthesized TiO2 photocatalyst exhibits photocatalytic activity against some common pathogenic microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus under visible light illumination. TiO2 is known to exhibit photocatalytic activity under UV light irradiation, the results obtained in this study using solar irradiation are very promising and enables the use of cheaply available solar energy for the process of photocatalysis.