Abomasum mucosa of new born ruminants during the first days of their life produces highly specialized milk-clotting aspartic proteinase -chymosin. The synthesis of a homologous enzyme, characteristic for adult animals-pepsin, starts later. Bovine chymosin has been thoroughly studied, whereas no available literature has been found on isolation and characterization of respective enzymes from domestic buffalo (BOS BUFFALI L) abomasum, although buffalo rennet is routinely applied for cheese making, particularly in Egypt. Therefore, this study was suggested to isolate chymosin from commercial preparation of buffalo calves rennet, in order to cast more hight on the properties of this enzyme.