The kinetics of the enzymic hydrolysis of palm oil using lipase in a batch reactor has been investigated. The lipase enzyme used was not ester bond position selective and its activity at the interface was higher compared to that in the bulk. A mathematical model taking into account the mechanism of the hydrolysis reaction and the effect of interfacial area between the oil phase and the aqueous phase containing the enzyme was developed. A correlation between the interfacial area and the operating conditions including agitation speed and oil volume fraction was established experimentally. The kinetic parameters were estimated by fitting the data to the model and comparing with previously reported values. The kinetic model represented the experimental data accurately. (C) 2002 Elsevier Science Ltd. All rights reserved.