Background: Defective or immature antibody responses to pathogens in children may explain the increased susceptibility to acute otitis media. However, there is no study in Korea patients whether a correlation exists between otitis media with effusion and the levels of serum immunoglobulins, IgG subclasses, IgA, IgM and IgE. Methods: 45 children with otitis media with effusion more than 4 episodes in 12 months or 3 episodes in 6 months, 62 children with otitis media with effusion less than 3 episodes in 12 months and 102 children for control group took part in the study at the Department of Otorhinolaryngology of the KyungHee University from May 2004 to Feburary 2007. Serum immunoglobulin levels were determined by nephelometry. And then the relationship between otitis media with effusion and serum immunoglobulin level was evaluated. Results: In otitis media prone group, serum IgG1, IgG2, IgG4, and IgA level was lower than those level of control group, it was significantly decreased (p<0.05). In otitis media group, serum IgA, IgE, and IgG4 level was lower than those level of control. But it was not statistically significant (p>0.05). Conclusion: Lower immunoglobulins in children with otitis media with effusion suggest a generalized decreased antibody responses. Lower levels of serum IgG1, IgG2, IgG4, and IgA may be related with chronicity or intractability of otitis media with effusion.