The published studies about the water quality of Euphrates River in Iraq till now have been reviewed critically. The revision of the published researches depend upon several bases including the period of samples collection, the number of sampling stations, water samples collection method, the analytical techniques employed to measure and analyze the results. This critical study concluded that the need to follow a specific protocol in selection sampling sites, how the samples are collected, how samples are analyzed, and pay attention to quality assurance and quality control during sample collection, preservation and analytical procedures.