Newcastle disease (ND) vaccination was targeted to reduce mortality, viral load in the environment, and eradication of positive cases. Many immunostimulants have been used to improve the immune response of vaccinated chickens. The current study was designed to compare the effect of different immunostimulants on immune response of NDV vaccinated chicks. A total of 150 one-day old Cobb chicks were divided into 5 equal groups. Group 1 was lifted as non-vaccinated negative control, whereas other groups were vaccinated against NDV. The used immune stimulants under test were given to groups 3, 4, and 5 as follows N. sativa 6%, curcumin1%, and orego sol. respectively at 7th day old continuously till the end of experiment. The results showed high antibody titers, low mortality rates and better body performance in the groups treated with these immunostimulants than the other groups. However, chicks treated with N. sativa showed renal water cyst formation compared with other groups. In conclusion, application of immunostimulants can stimulate the immune response and reduce the pathogenicity of ND in chickens.