A herpesvirus was isolated from the liver of a captive-bred American kestrel (Falco sparverius) which had died of inclusion body disease. Initial isolation was achieved in chicken embryo fibroblasts after three blind passages. Cell-adapted virus produced a distinct rounding of CEF cells within 24 to 48 h. Biologic and serologic tests suggested that the kestrel virus is similar to falcon herpesvirus and pigeon herpesvirus and is at least partially related to owl herpesvirus. However, serologic tests indicated that the kestrel herpesvirus is neither related to infectious laryngotracheitis virus nor to a herpesvirus from a psittacine bird; (Eupsittula canicularis) with Pacheco's parrot disease. This is the first report on the recovery of a herpesvirus similar to falcon herpesvirus from an American kestrel with naturally-occurring inclusion body disease, and on the serologic comparison between falcon herpesvirus and a psittacine herpesvirus.