Quail, chickens, and turkeys vaccinated with pigeon and fowl pox viruses were not protected against challenge of their immunity with quail pox virus and they developed severe cutaneous lesions of pox. When quail and chickens were vaccinated with quail pox virus and given pigeon and fowl pox challenge viruses, no protection was present. Thus, quail pox virus had no immunologic relationship to pigeon and fowl pox viruses. Psittacine pox virus applied as a vaccine in quail and chickens also failed to protect against quail pox virus challenge. However, quail, chickens, and turkeys vaccinated with quail pox virus were protected against quail pox virus challenge. An isolate of psittacine pox virus, applied as a vaccine, protected chickens against challenge with the same virus isolate and also against challenge with two other psittacine pox virus isolates, confirming a close or identical antigenic relationship with each other. When combined in a multivalent vaccine, quail, psittacine, and fowl pox viruses induced excellent protection in chickens against challenge with the three respective viruses. The presence or absence of "takes" or reactions following vaccination by the wing web route did not necessarily correlate with the presence or absence of immunity noted from challenge by feather follicle virus application. The role of quail and psittacine pox viruses as potential pathogens for poultry was discussed briefly.