A new method for immobilizing lipase in microcapsules prepared by in situ polymerization of divinylbenzene and the interfacial reaction of calcium chloride with sodium silicate were examined. The mean particle sizes of the organic and inorganic microcapsules prepared were 63.3 and 34.7 mu m, respectively. While the reaction rate of the encapsulated lipase was low compared with that of free lipase, the hydrolysis reaction proceeded successfully. The rate data on both microcapsule systems apparently obeyed Michaelis-Menten type kinetics. The low reaction rate of lipase encapsulated in the organic microcapsules was considered to be caused by thermodeactivation of lipase during polymerization. The encapsulation of lipase by the interfacial reaction of calcium chloride with sodium silicate was not a suitable immobilization method, since the lipophilic substrate diffused through the hydrophilic inorganic wall of the microcapsule.