Porcine pancreatic lipase (PPL) was covalently immobilized through the formation of an aromatic Schiff＇s-base obtained by reaction of the epsilon-amino group of lysine residues in the enzyme and the aromatic aldehyde function of activated supports. The enzymatic activities of different immobilized PPL systems on amorphous AlPO4 and several inorganic supports at different pH values and temperatures were determined by hydrolysis of ethyl acetate. The nature of the support material critically affects the efficiency of enzyme immobilization as well as enzyme stability. All the supports examined, with the exceptions of cellulose and natural sepiolite, exhibited good properties for enzyme attachment. AlPO4 was the best support for enzyme immobilization, giving the highest percentage binding of enzyme (90%) and the highest retention of enzyme activity after immobilization (92.8%).