Abstract: Fundamental liquid-liquid equilibria data are very important in modeling and design of the extraction process. To provide fundamental data for the extraction process of phenol removal from wastewater, experimental liquid-liquid equilibrium data in the range of dilute phenol concentration were determined for the ternary system methyl isobutyl ketone (MIBK)-water-phenol at 25℃, 40℃ and 50℃ under atmospheric pressure. The experimental data were correlated with the NRTL model, and binary interaction parameters of the ternary systems were obtained. The predicted data calculated by using the regressed parameters showed that the experimental data were successfully correlated with the NRTL model. The relative root mean square deviations and absolute mean deviations between calculated and experimental values were less than 2%.