The review discusses the challenges and current technologies used for treating produced water, the largest waste stream in the oil and gas industry. Produced water is a mixture of organic and inorganic compounds, and its environmental impact has become a significant concern. Traditional treatment methods, including physical, chemical, and biological approaches, are often used, but they have limitations, such as the inability to remove small suspended oil particles and dissolved elements, and the high costs and environmental impact of chemical treatments. Offshore platforms typically use compact systems due to space constraints, while onshore facilities can benefit from cost-effective and environmentally friendly biological pretreatment. The high salt concentration and variations in influent characteristics can affect effluent turbidity, necessitating the use of physical treatments like membranes. Future research should focus on optimizing existing technologies and combining physico-chemical and biological treatments to meet reuse and discharge standards. Keywords: Oilfield brine; Oilfield wastewater; Produced water; Treatment technology.The review discusses the challenges and current technologies used for treating produced water, the largest waste stream in the oil and gas industry. Produced water is a mixture of organic and inorganic compounds, and its environmental impact has become a significant concern. Traditional treatment methods, including physical, chemical, and biological approaches, are often used, but they have limitations, such as the inability to remove small suspended oil particles and dissolved elements, and the high costs and environmental impact of chemical treatments. Offshore platforms typically use compact systems due to space constraints, while onshore facilities can benefit from cost-effective and environmentally friendly biological pretreatment. The high salt concentration and variations in influent characteristics can affect effluent turbidity, necessitating the use of physical treatments like membranes. Future research should focus on optimizing existing technologies and combining physico-chemical and biological treatments to meet reuse and discharge standards. Keywords: Oilfield brine; Oilfield wastewater; Produced water; Treatment technology.