Inactivated Newcastle disease virus (NDV) vaccines were prepared using paraffin oil, paraffin oil and aluminum stearate (Al.St.) and Montanide oil ISA 71VG as adjuvants. All experiments gave the priority to the inactivated NDV vaccines with paraffin oil adjuvant and Al.St. 4- 5 mg/dose including stability (drop test, centrifugation and real time test) and viscosity (dynamic and relative) over NDV vaccine adjuvant with paraffin oil alone that showed reduced stability, however NDV vaccine with paraffin oil and Al.St. 6mg/dose and 7mg/dose showed high values of viscosity indicating hard injectability. Chicks vaccinated with inactivated NDV vaccines with paraffin oil adjuvant and Al.St. (4, 5, 6 and 7 mg/dose) gave higher cell mediated immune response (lymphocyte blastogenesis and macrophage activity), humoral immune responses (using haemagglutination inhibition test) and 100% protection upon challenge experiment in comparison to that vaccinated with NDV vaccine with paraffin oil adjuvant alone that showed 93.3% and 86.66% protection for vaccines used immediately after preparation and the others used after one year of storage at 4°C, respectively. Chicks vaccinated with NDV vaccines with paraffin oil adjuvant and Al.St showed slightly lower values of both cellular and humoral immune responses than that of NDV vaccine adjuvant with Montanide ™ ISA 71VG. In conclusion, inactivated NDV vaccine prepared with paraffin oil adjuvant and aluminum stearate (4 mg/dose and 5 mg/dose) were superior for that adjuvant on paraffin oil alone, as they improved stability and potency of the vaccine, and were with the same quality to that of NDV vaccine adjuvant on the imported Montanide ISA 71VG.