An important disease that is economically important among the dairy cattle is mastitis. Its control is somehow complicated by high standard resistance to antibiotics. Hence, there is alternative way to control bacterial infection and contamination by phage therapy. In the present research we checked the effect of temperature and pH on the stability of bacteriophage against staphylococcus aureus causing mastitiswhich is isolated from the sewage water of dairy farm. The bacteriophage showed lytic activity against these bacteria. The lytic activity of bacteriophage at varying temperature and pH established their stability range while their highest lytic activity was observed at 37 C and pH 7.0. The storage condition of -20 C was proved to be best for the phage. The phage efficiently reduced bacterial growth in the bacterial reduction assay.So it signifies the underlying potential of bacteriophage therapy.