This publication arises from a Coordinated Research Project and contains the results of the interactive collaboration of the chief scientific investigators, research agreement holders, research contract holders and IAEA experts to assess, improve and finally economically analyse the impact of vaccination against Newcastle disease, Gumboro disease and fowl-pox, as well as management strategies. The publication will be of use to poultry specialists involved in the diagnosis and control of infectious diseases, field veterinarians confronted with poultry production problems, and veterinary authorities planning such control programmes. It also contains a wealth of data useful for teachers and students at veterinary universities and colleges.