In the spring of 1993, an outbreak of respiratory infection affected 113 persons (103 males) in Jedl'ové Kostol'any, a village located in a hilly area of western Slovakia. Q fever, manifested as a flu-like illness with atypical pneumonia and hepatic involvement, was diagnosed using four serological tests (microimmunofluorescence, microagglutination, complement fixation, and enzyme immunoassay). Aborting goats were proven as a source of infection. During a 4-year follow-up study, no chronic form of Q fever could be demonstrated, either clinically or by tests to detect phase I Coxiella burnetii antibodies.