Technical Abstract: Avian influenza (AI) in domestic poultry is a national and international issue that negatively impacts animal health and trade in poultry and poultry products. Control programs for AI in poultry varies from tolerance of endemic low pathogenicity forms of AI to the extreme of implementing total depopulation programs for eradication of high pathogenicity AI. Vaccines have been used in control and eradication programs for AI based on needs of individual countries. Vaccine-induced protection is based upon antibodies produced against the surface glycoproteins, principally the hemagglutinin, but also the neuraminidase. This protection is specific only for individual subtypes of hemagglutinin (H1-15) and neuraminidase (N1-9) proteins. Avian influenza vaccines protect chickens and turkeys from clinical signs and death, and reduce respiratory and intestinal replication of a challenge virus containing homologous hemagglutinin protein. AI vaccines will not consistently prevent total replication of challenge virus; i.e. "sterilizing immunity." Vaccination should only be viewed as a single tool in an overall comprehensive control strategy that utilizes the practice of strict biosecurity, proper disinfection, limited human access to farms, adequate surveillance and quarantine measures, and methods of low risk elimination and disposal of infected birds.