The purpose of this study was to evaluate eosinophil infiltration as well as IL-5 and eotaxin levels in middle ear effusion (MEE) and blood from otitis media with effusion (OME) patients with asthma and to compare the findings with those from OME patients without asthma (control group). Levels of IL-5 and eotaxin in MEE and blood were measured by means of enzyme-linked immunosorbent assay. 5 levels in MEE were significantly higher than those in blood in both groups of patients and in OME patients with asthma than in the control group. In addition, in OME patients with asthma, there was a significant correlation between the percentage of eosinophils and IL-5 levels in MEE. Eotaxin levels in blood were significantly higher than those in MEE in both groups of patients and in OME patients with asthma than in the control group. In addition, in OME patients with asthma, the percentage of eosinophils and eotaxin levels in blood tended to correlate, but did not reach statistical significance. These data suggest that, in OME patients with asthma, eosinophilia in MEE depends more on IL-5 than on eotaxin, and that eotaxin may play an important role in the mobilization of eosinophils from the bone marrow into the blood.