Coxiella burnetii is the causative agent of Q fever. It can manifest in both acute and chronic forms. Culture-negative endocarditis is the most common and serious presenting form of chronic Q fever. This occurs almost exclusively in patients with a pre-existing valvulopathy including valve prosthesis or immunocompromised patients as well as in pregnant women. Diagnosis is often delayed or missed due to the nonspecific symptoms of the condition. Without the proper antimicrobial therapy, the mortality is high. Q fever endocarditis should be suspected especially in people who recently had acute Q fever, people who come from endemic areas as well as people with occupational contact with sheep, goats and cattle and endocarditis symptoms. In this article we present a case with a patient who died of unknown cause and where PCR performed on autopsy of the valve revealed Q fever endocarditis.