Two experiments were conducted to determine the effect of addition of vitamin E on the infectivity titer of NDV vaccine (Clone 30), humoral immunity and protection against challenge in broiler chickens. The work done in this study has given a good evidence on the role of vitamin E when used during vaccination against NDV. In experiment one, the results given showed that there was a slight decrease in the titer of vaccinal strain of NDV (Clone 30) when inoculated with different concentrations of vitamin E. on the other hand, results of experiment two revealed that vitamin E plays a complementary role in the immune response (humoral immunity) of broiler chickens.