In Egypt, Newcastle disease virus (NDV) outbreaks are occurring frequently, researchers try to study epidemiology of the virulent NDV isolates from these outbreaks. Velogenic & mild NDV strains was successfully isolated in Egypt from 1950 till now. NDV  still  reported  to  cause  severe  outbreaks  with  high  losses  in  infected  flocks  during  2005,  velogenic  NDV  caused  outbreaks  among  commercial  chicken  in   Egypt   so, it is obligatory to study the protective immunity of commercially  available  vaccines  for  prevention  and  control  of   the disease. VIIb NDV genotype was previously described as the predominant sub-genotype of genotype VII circulating with severe outbreaks in Egypt in last decade.