We present here a patient with acute myeloid leukemia (M2) who developed fatal infective endocarditis. On admission, the patient (67-year-old male) had mitral stenosis and atrial fibrillation. Complete remission was achieved after induction chemotherapy. During the course of consolidation therapy, he developed sepsis caused by coagulase-negative staphylococcus, which was successfully treated with antibiotics. Thereafter, blood culture yielded multidrug-resistant staphylococcus epidermidis. An echocardiogram revealed mitral valve regurgitation with vegetation. He was diagnosed as having infectious endocarditis. In spite of prolonged antibiotic therapy, destruction of the mitral valve progressed, and the patient underwent valve replacement therapy. He died of cardiac tamponade 5 days after the surgery.