TiO2 is one of those compounds which are highly used in photocatalytic degradation of substrates using UV radiation. The substrates are degraded oxidatively and hence finds an important position in advanced oxidation for water/wastewater treatment processes. The thrust of this research was to evaluate the effectiveness of Heterogeneous Photocatalysis (HP) technique, for the removal of pesticides from water/wastewater. The photo-catalytic degradation of two pesticides, widely used in India, viz., Endosulfan (ES) and Chlorpyriphos (CPS) was studied in an annular slurry photo reactor under UVillumination at 254 nm. Results revealed that the degradation rate is significantly affected by the initial pesticide concentration, pH of the solution and catalyst concentration. Batch degradation studies on Endosulphan and Chlorpyrifos were conducted in the concentration range from 5 to 25 mg/L at a pH ranging from 3.5 to 10.5 and at a catalyst loading of 0.5–2 g/L. Endosulphan removal efficiency was about 80–99% and chlorpyrifos removal efficiency was about 84–94%. L–H rate constants were determined using L–H kinetics. High removal efficiencies obtained (80–99%) indicate the effectiveness of this process and its potential for practical application. © 2015 Elsevier Inc.