Acute otitis media and otitis media with effusion are common diseases of children. Though related to each other, they are clinically separate entities. In order to assess the effectiveness of medical interventions it is important to know the epidemiology of the condition. This paper reviews the incidence, natural history and risk factors for otitis media. In most cases acute otitis media and otitis media with effusion are self-limiting disorders. Complications and an abnormal course are rare. There are, however, subgroups of otitis-prone children, identifiable on the basis of risk factors. These children need special attention from the general practitioner, for example a more frequent use of medical interventions and surveillance. It is important to realize that individual and family factors have more influence on the outcome of otitis media than do the various available medical interventions.