Otitis media with effusion (OME) is the presence of fluid within the middle ear without signs or symptoms of middle ear inflammation. It is one of the commonest pathologies of childhood, with most children having evidence of middle ear fluid at some stage of their development. Otitis media with effusion may occur in isolation, or be associated with recurrent acute otitis media (RAOM). It can also be associated with other ear nose and throat issues including adenoid hypertrophy, allergic rhinitis, recurrent tonsillitis, and obstructive sleep apnea. While there is not always a definitively demonstrated causal relationship between these conditions, their presence or otherwise will have an impact on treatment for the ears. The role of the primary care physician and otolaryngologist is to identify the patients for whom OME is likely to persist, and for whom it is likely to have a negative developmental consequence if not treated. A brief discussion on epidemiology, pathophysiology, assessment and treatment of OME have been presented in this chapter.