In the present study, Lactoperoxidase system (LPS) was activated in fresh cow's milk. The pH and acidity of treated milk were followed during storage at room (32°C), incubator (37°C) and refrigerator (5 ±1°C) temperatures. The activation was done using SCN ◌and H2O2 or SCN ◌and Na2CO3.1.5 H2O2. The effect of activation on microbiological quality was also investigated. All the treatments greatly improved the keeping quality of milk at room or higher temperatures compared to the untreated samples. The best results were achieved by adding 14mg SCN /L: 2mL H2O2/L to cow's milk. In addition, slight improvement in the keeping quality of the LP-activated milk was observed when the milk was kept in a refrigerator. kareish cheese was made from cow's milk preserved by the LPS and the effect of the LPS on the chemical, microbiological and sensory properties of kareish cheese storaged for 30 days was investigated. Kareish cheese made from LPactivated cow's milk was low in the total bacterial count when compared to cheese made from the untreated one (control). The LP treatment did not affect the overall chemical composition of the cheese. Activation of LP system allowed to produce of kareish cheese with high and keeping quality.