The kinetics of the acidolysis of butter oil with conjugated linoleic acid in the presence of an immobilized lipase from Candida antarctica has been investigated. A uniresponse kinetic model was developed to characterize the rate of consumption of the conjugated linoleic acid and the total rate of release of the fatty acids formed from butter oil. In addition, a multiresponse kinetic model was developed to characterize the individual rates of release of the major fatty acid residues present in the original butter oil. Limited hydrolysis (2-4%) was also observed.