In 1968, Hardy and Anderson first described the term hypereosinophilic syndrome. This syndrome is characterized by persistent and prolonged eosinothila, with primarily hematologic, cardiac, neurologic and derrnatologic abnormalities. Cutaneous mmestations occur in 27-57% of patients. Two types of skin lesions have been noted: (1) erythrritous pruritic papules and nodules or (2) urticaria and angioedema. We report a case of hypereosinophilic syndrome with a vesicle eruption which is a rare skin lesion in tbis syndrome, in a 17 year old man. Diagnosis of hyprcsinophilic syndrome was established by clinical findings, rearked blood eosinophilia without a Brown cause, bone marrow aspiration and biopsy, liver scan and ultrasonography, and histopatholcgie findings of the skin. (Kor J Dermatol 1995; 33 (2): 332-338)