Fibroblastic endocarditis is a classic complication of prolonged hypereosinophilic syndrome, whatever the cause. In France, it is most frequently encountered in cases of idiopathic hypereosinophilic syndrome. It commonly involves the apex of the ventricles, with a clinical picture of restrictive cardiomyopathy of unfavorable prognosis, and the auriculoventricular valves. We report the case of a 77-year-old man in whom atypical cardiac involvement disclosed idiopathic hypereosinophilic syndrome. In addition to the usual features of obliteration of the apex and restrictive cardiomyopathy, echocardiographic examination showed severe left ventricular dysfunction and intracardiac tumors, one of which was unusually localized to an aortic valve. Treatment, which comprised strict control of the eosinophilic process, standard treatment for cardiac failure, and anticoagulation therapy, produced rapid and long-lasting improvement of his clinical status and left systolic and diastolic ventricular function, and on echocardiography the intracardiac tumors had totally disappeared. The patient suddenly died of septic shock 16 months after first being seen.