For the effective enzymatic hydrolysis of olive oil, the potential of reverse-phase as a new reaction system was tried. Lipase was immobilized by adsorption in macroporous, organic synthetic resin, Amberlite XAD-7, and the catalytic reaction of immobilized lipase is performed on reverse-phase system which is composed of waterinsoluble substrates and immobilized enzyme dispersed in nonpolar solvents. The optimum conditions for lipase immobilization, such as immobilization times, and amount of enzyme to be attached to the resin were investigated. Isooctane was found to be the most effective organic solvent of the nine types of organic solvents tested for the hydrolysis of olive oil. The immobilized enzyme did not obey Michaelis-Menten kinetics and optimal conditions of reaction were 35$^\circ$C and pH 6.0. The enzyme activity was affected by stirring rates. Batch hydrolysis of olive oil by lipase in reverse-phase has been also carried out. Olive oil (10\%, v/v) can be completely hydrolyzed within 5 hr.