In a flock of sheep the causal connection between abortions and the infection with Coxiella burnetii is demonstrated serologically, bacteriologically and by pathological examination. In order to identify C. burnetii as causing agent in case of abortions the submission of placental parts in addition to the fetus, in combination with a serological control of the flock, is recommended. To check the seroprevalence of C. burnetii in the region concerned random blood samples of 12 flocks were taken and analysed by CFT. At least 10 samples per herd, taken from animals more than 1 year old, were examined. Positive titers were found in 5.6% of the checked animals which originated from 6 different flocks. Health risks of different groups of the human population are being discussed.