Bartonella spp are important causes of culture-negative endocarditis, generally causing a subacute insidious form of endocarditis, often leading to a delay in diagnosis. Most patients have fever and often present with signs and symptoms of heart failure. The diagnosis is frequently established only on meticulous examination of the resected heart valve with the polymerase chain reaction technique. We present a case of B quintana mitral and aortic valve endocarditis with associated severe valvular insufficiency and decompensated heart failure precipitated by Streptococcus pneumoniae bacteremia, necessitating urgent surgical valve replacement. Pathologic examination of the valve complemented by serologic and molecular testing established the surprising diagnosis of B quintana endocarditis.