This family of mites contains more than 100 species of blood-sucking ectoparasites. The main hosts are birds and mammals. Several species are pests of poultry and some can also infest humans causing dermatitis. Further, several species transmit rickettsial and virus diseases. Important pest species are for example the northern fowl mite, Ornithonyssus sylviarum, and the tropical rat mite, Bdellonyssus bacoti.
The following genera and individual species are currently entered under this family: