The May-Hegglin anomaly is characterized by thrombocytopenia, giant platelets and inclusion bodies in granulocytes. This disorder is inherited as autosomal dominant traits and has been reported in only 2 families in Korea. We experienced May-Hegglin anomaly in a 46-year-old woman who visited the Dermatology outpatient Clinic for care of brown pigmentation around the bilateral periorbital area. This pigmentation occurred after trauma several years ago. The patient had a history of hematuria one year prior to visit and was diagnosed as having idiopathic thrombocytopenic purpura. One of her sisters also had a history of severe bleeding during the surgery in an other hospital about one year ago, and had been diagnosed as having myelodysplastic syndrome by bone marrow biopsy. In peripheral blood smear both patient and her sister were noted to have thrombocytopenia, giant platelets and basophilic inclusion bodies present in the granula-free zone of cytoplasm in the periphery of neutrophils and eosinophils. Transmission electronmicroscopy revealed abnormal cytoplasmic inclusions, in granulocytes. The inclusions were characterized by parallel collection of rough endoplasmic reticulum. The findings of bone marrow aspiration and biopsy were normal, except for the presence of basophilic inclusions in myelocytes. The results of PT, aPTT, bleeding time and platelet aggregation test were normal except for decreased aggregation to epinephrine.