This article aims at the presentation of endemic chlamydial colonizers of placenta in ewes. Chlamydophila abortus is the common bacteria causing enzootic abortion in sheep herds. Clinically, it is characterized by loss of lambs in late pregnancy, stillbirths or premature births of weak or dead kids. Retained placenta and vaginal discharge are common clinical signs. Lambs born with low birth weight developed polyarthritis. In rams C. abortus causes vesiculitis and epididymitis. Diagnosis of enzootic abortion is based on the detection of C. abortus antigens by ELISA or IF test, and nucleic acid of the causative agent by PCR, RT-PCR in the aborted fetuses, fetal membranes and vaginal discharge. Serological tests as CFT and ELISA may be also used, however their value is limited. Currently, two types of a vaccine, inactivated and attenuated, live vaccines, are available commercially, to be administered intramuscularly or subcutaneously at least 6 weeks before breeding, to aid in the prevention of ovine abortion. A multi-component, recombinant vaccines against C. abortus COMC, OG-COMC and recombinant vaccine MIP/CPAF remain a future goal of chlamydial vaccine research.