Abstract: The study in this thesis was a trial to evaluate the: "serological response of broiler chickens to Avian Influenza Virus common commercial vaccines which are currently used in Egypt, (the Chinese Vaccine, H5N1 and the Nobilis Influenza Vaccine, H5N2". The study was carried out on blood serum samples collected from broiler chickens, type: COBB AVIAN 48™ which came from previously AIV vaccinated broiler breeders.