Two nightjars (Caprimulgus europaeus) from a bird park in the Netherlands died suddenly, with no clinical signs, within 1 month of each other. The main pathologic findings at necropsy were splenomegaly and hepatic necrosis. On histologic examination, intranuclear viral inclusion bodies consistent with avian polyomavirus were observed in the liver, spleen, and kidneys. Polymerase chain reaction testing of samples from the liver, spleen, and kidneys detected avian polyomaviral DNA, and sequence analysis showed that the virus had a sequence homology of 99% to psittacine avian polyomavirus strains. To our knowledge, this is the first report of avian polyomavirus infection in the order Caprimulgiformes. Lovebirds (Agapornis species), which were housed near the nightjars, were considered as the possible source of infection.