Hydrolysis of olive oil in isooctane by lipase from Candida cylindracea in an aqueous solution was carried out in a polydispersed emulsion system prepared by a homogenizer and in a monodispersed emulsion system prepared by the shirasu-porous-glass (SPG) membrane emulsification method. An emulsion system consisting of both SDS and PVA at pH 7.8 was best suited for the reaction. In the monodisperscd emulsion, the droplet diameter was controlled by the pore diameter of the SPG membrane to give droplets with a narrow diameter distribution range. The rate of hydrolysis was affected by the concentrations of olive oil and lipase, the interfacial area and the emulsion droplets diameter. The kinetic data were interpreted by the interfacial reaction model, in which desorption of the product from the interface was the rate determining step. The equilibrium constant of the adsorption of Lipase at the interface were very small compared with that obtained in the isothermal adsorption equilibrium of lipase at the interface without a surfactant. The equilibrium constants of the reaction between lipase adsorbed at the interface and olive oil in the organic phase were nearly of the same order as those obtained in the Lewis cell and the VibroMixer. The desorption rate constants of the product were very large compared with that in the Lewis cell.