Q fever is a worldwide zoonosis caused by Coxiella burnetii. Looking to the duration of the disease, Q fever may be divided into acute and chronic forms. In humans, acute C. burnetii is often asymptomatic or mistaken for an influenza-like illness or atypical pneumonia. On the other hand, chronic Q fever is characterized by a spontaneous evolution lasting for > 6 months and a high level of IgG antibodies titre, generally determined by the indirect fluorescence antibody (IFA). However, other clinical manifestations may be observed, including hepatic, neurologic, dermatologic, and cardiac disturbs. Teha last one includes pericarditis, which has been observed in 1% of patients affected by C. burnetii infection. However, this incidence is probably underestimated. In fact, over 80% of acute as well as recurrent pericarditis remains aetiologically unexplained.We describe a case of a 36-year-old man reporting progressive onset of dyspnea, chest pain and dysthermia sensation. Ambulatory treatment was unsatisfactory developing a severe respiratory failure recquiring his admission in the Critical Care Department. Blood test showed discrete leukocytosis with left deviation and increased reactive protein C levels. Thoracic computed tomography (CT) showed a 22mm pericardial effusion with a bilateral pleural effusion more marked in the left lung area. Microbiological as well as serological studies showed positive IgM titers to C. Burnetii. Doxycycline treatment was initiated with postive results.