To increase the separability of benzene-cyclohexane mixture by liquid membranes with anionic and nonionic surfactants, lipophilic surfactants of different HLB values were injected into the external oil phase for the purpose of making the size of emulsion globules smaller. In the case of nonionic surfactant the fraction of permeation and the separation factor increased appreciably compared with those obtained without using lipophilic surfactants. In the case of anionic surfactants, however, the fraction of permeation and the separation factor did not increase appreciably compared with those obtained without using lipophilic surfactants. In general the percentage of membrane breakup was more when the lipophilic surfactants were added than not.