Abstract: Ahigh sensitive and selective micellar solubilizing spectrophotometric method is developed for the determination of microamounts of Cu²⁺ in the industrial effluents with o-nitro-phenylfluorone as color reagent and N-cetyl pyridinum chloride as solubilizing and sensitizing agent. The molar absorptivity of the system is ε_600nm=1.08×10⁵. The standard deviation and variation coefficient of the method are 0.37 and 2.1% (n=16) respectively. Beer's law is obeyed in the range of 2-8μg Cu²⁺/25ml. The new method has been used to determine micro-amounts of copper in various industrial effluents. The results obtained are good agreeable with those obtained by usuall diethyldithiocarbamate method. No organic solvent such as chloroform is used and the procedure is more simple and rapid.