OBJECTIVE: Otitis media is the most frequently diagnosed infection in the pediatric office. Ninety per cent of the children present at least one episode of otitis media before the fifth birthday. We reviewed the literature in order to update information regarding the current definitions of acute otitis media, recurrent otitis media and otitis media with effusion, analyzing the predisposing factors, microbiology, clinical manifestations, diagnostic criteria and methods of treatment for these entities, and the relationship between otitis media and language development and learning disabilities.DATA SOURCE: Bibliographic review of an eighteen- year period (1980-1998) using Index Medicus and Medline.RESULTS AND CONCLUSIONS: More than 25 million diagnoses per year of middle ear infections are made in the United States, being responsible for rising costs of treatment. The role of many predisposing factors is presently well recognized and we should be capable of defining interventions related to some of them as is the case of early institution of day-care, short duration of breast feeding and difficulties in the identification and treatment of gastroesophageal reflux. Changes in the microbiology of the middle ear infections and the emergence of multiresistant bacteria leads to modifications in antibiotic therapy and the duration of its use. Antibacterial agents should be prescribed only in the presence of a well-defined diagnosis and chemoprophylaxis should be avoided. Recurrent otitis media and otitis media with effusion in infants may be associated to speech disorders and learning disabilities. The development of a conjugated vaccine against S. pneumoniae and the experiments with a vaccine against non-typeable H. influenzae represent a big step in the prevention of infections of the middle ear for the near future.