This paper deals with the degradation of Fenitrothion (an agricultural organophosphorous pollutant) in aqueous solution by titania nanophotocatalysis. The immersion type method was used for the treatment of polluted water. UV-Vis, ion chromatography and chemical oxygen demand analyses were employed to obtain the details of the photocatalytic degradation and mineralization of Fenitrothion. The numerical model was used to solve mathematical equation describing pollutant degradation process. The simulation results were compared to those results obtained from experimental tests and close agreement was achieved. Results show that the immobilized