PURPOSE: Several studies have shown that increases of eosinophil markers are common findings of asthma and Mycoplasma pneumoniae infection, and eosinophil markers reflect the clinical stage of asthma. The purpose of this study was to investigate the change of eosinophil markers according to the clinical stage of Mycoplasma pneumonia. METHODS: The patient group consisted of 33 outpatient children with Mycoplasma pneumonia. Peripheral blood total eosinophil count(TEC) and serum eosinophilic cationic protein(ECP) level were measured at both acute and recovery stages and were compared between both stages. The patient group was subdivided into the wheezing(n=16) and the nonwheezing group(n=17), and the TECs and the ECPs of one group were compared with those of the other group. The correlation between Mycoplasma antibody titer and the eosinophil markers of acute stage were analyzed. RESULTS: In the whole patient group, the TECs and the ECPs of the acute stage were significantly higher than those of the recovery stage(P=0.018, P=0.005), but there were no differences in the TEC and the ECP between the wheezing and the nonwheezing group. In the wheezing group, there were no significant differences in the TEC and the ECP between acute and recovery stages. There were no correlations between acute stage Mycoplasma antibody titer and the eosinophil markers. CONCLUSION: Eosinophil markers reflect the clinical stage of Mycoplasma pneumonia and eosinophilic inflammations may continue even after the acute stage in wheezing patients with Mycoplasma pneumonia.