The patient was a 29-year-old woman. When she consulted a local physician with chief complaints of fever and fatigue of the extremities, cerebral infarction was detected on MRI, in addition to abnormalities found on ECG. Ultrasonic cardiography revealed the presence of a tumor in the left ventricle. Therefore, tumorectomy and endocardectomy were performed under extracorporeal circulation based on a diagnosis of cardiac tumor. Inflammatory cell infiltration into the ventricular wall was pathologically confirmed, and eosinophilia was observed preoperatively. Therefore, the patient was diagnosed as having endomyocardial fibrosis, which is rarely observed in Japan. The postoperative course of this patient was satisfactory, and the eosinophil count was normalized postoperatively. At present, this patient is being followed at the outpatient clinic.