Activated eosinophils is a major cell type to be mainly involved in allergic diseases. Recent studies also indicated that eosinophils play an important role in the pathogenesis of allergic bronchopulmonary aspergillosis/mycosis (ABPA/M) and eosinophilic asthma. The aim of this study is to clarify cellular characters of human eosinophils in patients with ABPA/M and their differences between ABPA/M and eosinophilic asthma.