An investigation was carried out to determine the corrosion behavior of carbon steel L80 in different waters produced in local crude oil under specific downhole conditions. Results indicated that the corrosion rate of this alloy remains within acceptable level when the water-cut was below 30%. However, the corrosion rate of the alloy started to increase gradually between 30 to 40% water-cut. This corrosion rate increased sharply when the water-cut surpassed 40% and reached a maximum at 100% water-cut. It was recommended that a corrosion inhibitor ought to be used when the water-cut exceeds 30% to maintain the integrity of this alloy under operating conditions. Keywords: Corrosion, water-cut, downhole, L 80 carbon steel, produced water.