This paper finds out appropriate treatement methods for wastewater of an Organophoshprus 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 deirable results were obtained with treatement scheme employing acidification, chlorination with NaOCl,suspended growth biological treatement, chemical precipitation for phosphorous removal and activated carbon treatement. Acidification of wastewater helps in by-product recovery aswell as reduction in COD upto 36.26;. Chlorination followed by biological treatement 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 treatement in the form of chemical precipitation (for phosphorous removal) and granular activited carbon is suggested.