Objectives: to report a case of hypereosinophilic syndrome which presented clinically acute coronary syndrome. Materials and methods: we describe a case of a 69-year-old woman with acute coronary syndrome and peripheral hypereosinophilia. Results: the condition rapidly evolved to severe heart failure. Coronary disease was excluded by cardiac catheterization. Systemic corticosteroid therapy was initiated and further secondary causes of hypereosinophilia were excluded.