The small passerines, canaries and finches, are social birds often bred and housed in flock aviaries. The aviary may be a mixed aviary housing different species or a breeding aviary concentrating on a single species. Multiple birds in contact with each other provide the means by which infectious disease can spread. Dietary and husbandry requirements vary for the species of passerines housed and can also influence disease outbreaks when they are less than optimal. Stress factors, including nutritional, husbandry (overcrowding, aviary maintenance), breeding, and the introduction of new birds, may play a significant role in disease outbreaks. An overview of viral, bacterial, fungal, and parasitic issues affecting passerines housed in aviaries will be addressed.