Background: Chronic otitis media (COM) is one of the most common childhood diseases. Its pathophysiology is complex and multifactorial. The role of specific mucin glycoprotein subtypes in OM is only recently being elucidated. Objective: To determine the relationship between middle ear fluid mucins and clinical variables of patients needing tympanostomy tubes (TT). Methods: Middle ear effusions (MEE) from children receiving TT were collected over a 2-year period. Western blot characterization of mucins MUC5B and MUC5AC along with chart review of age, gender, effusion viscosity, hearing loss >30 dB, history of allergies, and/or respiratory disease were performed. Results: MEE samples from 58 patients were available for analysis. Overall, MUC5B was significantly more often detected in middle ear fluid relative to MUC5AC (90% vs. 51%, p = 0.005). MUC5B presence was statistically associated with mucoid effusions relative to serous effusions (100% vs. 57%, p = 0.0064), MUC5AC presence was not significantly different in mucoid and serous fluid (55.1% vs. 37.5%, p = 0.447). Patients younger than 48 months were more likely to present with mucoid effusion, compared to those older than 48 months of age (p = 0.038). Finally, patients with effusions positive for MUC5B were younger than those with effusions negative for MUC5B (35.1 vs. 76 months, p = 0.045). No other variables correlated to either effusion viscosity or specific mucin content. Conclusion: Patients younger in age needing TT placement are more likely to present with mucoid effusions, predominantly containing MUC5B mucin. As such, we postulate a distinct pathophysiology for mucoid and serous effusions across ages in children with COM. (C) 2016 Elsevier Ireland Ltd. All rights reserved.