The present invention provides a nucleic acid vaccine which is protective against avian polyomavirus infection in a bird which is classified as bieng a member of the Psittaciformes order comprising a nucleic acid vaccine vector comprising a suitable eukaryotic cis-acting trnascription/translation regulatory sequence functionally linked to a nucleic acid encoding an immunogenic avian polyomavirus polypeptide. Methods for preventing avian polyomavirus infection in a bird classified as being a member of the Psittaciformes order are also provided.