In this paper, a stirred membrane permeation cell was used to investigate the interfacial transfer kinetics between two immiscible phases. The diffusion boundary layer resistances on either side of membrane and the intrinsic membrane resistance were first determined by measuring the fluxes of simple diffusions of acetic acid and iodine. The possibility of the application of this permeation cell for studying the kinetics of metal extraction was then examined. The extraction of vanadium(IV) from sulfate solutions with bis(2-ethylhexyl)phosphoric acid dissolved in kerosene was chosen as the model system. It was found that an easy-to-follow method was provided to eliminate the effect of diffusional resistances on the apparent extraction rates and consequently the intrinsic chemical reaction rates could be obtained.