A 5-year-old girl was admitted to our hospital due to fatigue and fever lasting for six months. She had systolic murmur in the mesocardiac and apex regions and hepatosplenomegaly. Laboratory evaluation revealed leukocyte and eosinophil counts of 176 and 144.32 x 10(9)/L, 3.4% blasts in bone marrow and monosomy 8. She developed pulmonary, cardiac, nervous system, ocular and bone involvement. Upon diagnosis of "chronic eosinophilic leukemia, not otherwise specified" (WHO 2008 classification), she received methylprednisolone, vincristine, cytarabine and 6-thioguanine. After hematopoietic stem cell transplantation from a full-matched sibling was performed, the patient expired due to graft failure and septicemia.