The stability of double emulsions or liquid surfactant membranes, which is an important topic in liquid membrane extraction processes, was investigated. The percentage of liquid membrane leakage which reflects the stability of the liquid surfactant membranes was measured as a function of time using sodium hydroxide as a tracer. Water-in-oil emulsions were prepared with SOLTROL 220, an isoparaffinic solvent, and solvent-extracted neutral oils, S100N and S500N. The surfactant studied was Span 80 (sorbitan mono-oleate). The influence of microdroplet volume fraction, surfactant weight percent, agitation speed, and emulsifying device on leakage was studied using a half fraction of 24 experimental design. Microdroplet volume fraction and percent surfactant showed significant effect on the extent of leakage in the case of SOLTROL 220 runs at the 99% level or better. For runs with S100N, the effect of emulsifying device and that of percent surfactant on the rate of leakage was found to be significant at the 99 and 95% level or better, respectively. Several interactions between variables were also significant. Emulsions prepared with solvent extracted neutral oils, S100N and S500N, were quite viscous, which limited the influence of factors being considered on the extent of leakage.