Abstract: Liquid membrance extraction are a new and effective technique for separation of mixtures. They are made by forming an emulsion of two immisicible phases and then dispersing the emulsion in a third phase(the continuous phase). In this paper, we have treated the phenolic waste water, which contains 300-950 ppm of phenol, with liquid membrance, i. e. NaOH solution in oil. In proper condition, 98% of phenol may be removed and the breakage of the emulsion drops are less then 1 % per hour. The overall diffusivities of phenol through the liquid membrance are also calculated and they show to be a constant.