Inactivated oil emulsion vaccine of Newcastle disease virus (NDV) was prepared using heat resistant (HR) strain of NDV. Formalin and binary ethyleneimine (BEI) were used as inactivator with different concentration to determine the best inactivator and best concentration from each one. Experimental batches of inactivated HR strain of NDV Suspension were prepared by .sing BEI and formalin as inactivator of concentration of 0.001% and 0.03%, respectively. Paraffin oil adJuvant as used in the prepared oil emulsion vacine composed of different antigen concentration MAR strain, The efficacy and potency of inactivated HR strain of NDV were evaluated by haemagglutination test (HA), cell mediated immune response, macrophage activity, haemagglutination on inhibition test (HI) and challenge test in Chicken groups. The results revealed that BEI was the best inactivator which did not affect the activity of HA titres, In addition the economic use of ER strain of NDV in oil emulsion inactivated vaccine either inactivated with BEI or formalin gave good immune response and 100% protection either in low or high antigen concentration due to its high EIDsq over 1020/ml.