Idiopathic hypereosinophilic syndrome (IHES) is characterized by sustained, nonreactive hypereosinophilia with eosinophilia-associated organ damage. Cardiac involvement occurs in about 60% of patients with HES and it is the major cause of mortality in these patients. Cardiac dysfunction is reversible only after early corticosteroid (CS) initiation.Herein we report a 33-year old male who was referred to our Cardiology Department with electrocardiographic and echocardiographic abnormalities suggesting myocardial infarction. At presentation he complained of dyspnea, cough and persistent fever. His white blood cell (WBC) count was elevated, with eosinophil predominance in the differential. After cardiological and haematological work-up, the final diagnosis of HES-associated cardiac involvement was established. Early treatment with CS led to eosinophil count normalization with only moderate cardiac function improvement. Currently, the patient is in good condition overall and is in NYHA class II while still on prednisone.