A murmur of aortic regurgitation was discovered in an asymptomatic patient who had suffered from an acute Coxiella Burnetti infection several months before hand. Transoesophageal echocardiography, serology and direct immunofluorescence of the aortic valve confirmed the diagnosis of Q fever endocarditis. Treatment with Vibramycin and Plaquenil was instituted after aortic valve replacement. Cardiac complications of Q fever should be recognised as they may remain asymptomatic for long periods of time. Transthoracic and transoesophageal echocardiography should be widely used in acute forms of Q fever and systematic in chronic infections with Coxiella Burnetti.