Abstract
A sheep farmer's wife who had been assisting with lambing developed an influenza like illness in the 28th week of pregnancy. After five days of malaise she spontaneously delivered a stillborn infant; she became acutely ill during the immediate postpartum period with septicaemic shock, acute renal failure, and disseminated intravascular coagulation. The diagnosis was made by isolation and identification of Chlamydia psittaci from the placenta, fetal heart blood, and fetal lung, together with maternal serological evidence. The prominent histological and ultrastructural appearances of the chlamydial placentitis are described.