This paper finds out appropriate treatment methods for wastewater of an Organophosphorus viz, chloropyrifos pesticide manufacturing industry. The characterization of wastewater generated during trial production of chloropyrifos was carried out. Based on the characterization of wastewater, various treatability studies were conducted. The most desirable results were obtained with treatment scheme employing acidification, chlorination with NaOCl, suspended growth biological treatment, chemical precipitation for phosphorous removal and activated carbon treatment. Acidification of wastewater helps in by-product recovery as well as reduction in COD upto 36.26%. Chlorination followed by biological treatment was found to be effective to reduce the COD level by 62.06%. To comply with permissible limits prescribed by Effluent Channel Project Ltd.(ECPL)* and Gujarat Pollution Control Board (GPCB) for discharge of industrial effluent into channel, further treatment in the form of chemical precipitation (for phosphorous removal) and granular activated carbon is suggested.