Chusid et al proposed diagnostic criteria of hypereosinophilic syndrome (HES) that remain valid today. These were, (1) a sustained peripheral blood eosinophil count of more than 1500/L present for longer than 6 months ; (2) no evidence of other apparent causes for eosinophilia, and (3) presumptive signs of parenchymal organ involvement. Any organ system may be affected in HES, but the most severe clinicopathological involvements are of the heart and nervous system. Although multiple organ systems may be involved, the most common cause of morbidity and mortality is cardiac involvement with extensive fibrous thickening of the endomyocardium and overlying thrombus. We report a case of acute peri-myocarditis with eosinophilia, which was confirmed as eosinophilic myocarditis by endomyocardial biopsy, with literature review.