In this paper, the degradation and mineralization of Butachlor in aqueous solution by nanophotocatalysis using immobilized TiO 2 nanoparticles were investigated. Butachlor (N-butoxymethyl-2-chloro-2′,6′-diethylacetanilide) is a persistent organic pollutant in agricultural soil and watercourses. A simple and effective method was used for immobilization of titanium dioxide nanoparticles. UV–vis and Ion Chromatography (IC) analyses were employed to obtain the details of the photocatalytic degradation and mineralization of Butachlor. The effects of operational parameters such as H 2 O 2 , inorganic anions (NO 3 − , Cl − and SO 4 2− ) and pH were investigated. The lack of any absorbance in 254nm was indicative of the complete degradation of aromatic intermediates. The mineralization of Butachlor was evaluated by monitoring of the formed inorganic anions (NO 3 − and Cl − ). Butachlor is effectively degraded following first order kinetics model. Results show that the immobilized titanium dioxide nanoparticle photocatalysis is an effective method for treatment Butachlor from contaminated water.