A fresh pragmatic classification of the rickettsias has been derived by applying the simplest techniques of
numerical taxonomy. One order, the Rickettsiales, containing 3 families, the Rickettsiaceae, Phagosomaphilaceae,
and the Bartonellaceae (?) is proposed. Cowdria is classified as a genus along with Chlamydia, Coxiella
and Anaplasma in the tribe Chlamydieae in the family Phagosomaphilaceae.