Determination of trace uranyl ions was performed by using mixed micellar system and spectrophotometric determination. The method is based on cloud point extraction of uranyl ions after formation of an ion-association complex in the presence of Celestine Blue and sodium dodecyl sulfate. Then, the formed complex was extracted to non-ionic surfactant phase of Triton X-114 at pH 8.0. The optimal extraction and reaction conditions (e.g. concentrations and types of surfactants, concentration of complex forming agent, incubation conditions) were studied and analytical characteristics of the method (e.g. limit of detection, linear range, pre-concentration factor) were obtained by experimental studies. Linearity was obeyed in the range of 50-1,500 ng mL(-1) for uranium(VI) ion and the detection limit of is 14.20 ng mL(-1). The interference effects of common ions were also tested and validation studies were performed by using recovery test. The method was applied to the determination of uranium(VI) in several real samples.