© 2020 Turkish Society of CardiologyQ fever is a zoonotic disease caused by Coxiella burnetii, an obligate intracellular bacterium, which cannot be grown using routine blood culture methods. Although C. burnetii is reported to be the causative agent in approximately 50% of blood culture-negative infective endocarditis cases in developed countries, the incidence in Turkey is yet to be defined. The clinical course of Q fever endocarditis is generally subacute and chronic; the disease may be present for years with only subtle symptoms and no vegetation visible on echocardiography while the bacteria gradually destroy the heart valves. This is the case of the successful treatment of a young man with Q fever endocarditis that had an acute clinical course. In 1 month, he developed New York Heart Association class IV heart failure and a large, 3-cm vegetation was observed on an echocardiogram.