The epidemiology, pathogenesis, diagnosis, complications and sequelae, and therapy of otitis media are reviewed. Otitis media is one of the most common infections in infants and children. Epidemiologic studies have identified season of the year, bottle versus breast feeding, socioeconomic status, race, sex, and daycare attendance as factors associated with the occurrence of otitis media. The condition is believed to arise secondary to eustachian tube dysfunction in the presence of viral or bacterial invasion of the nasopharynx. Diagnosis is often made by direct observation of the tympanic membrane with an otoscope. If untreated, the infection can spread to other structures in the aural cavity or even to the brain and meninges. The most frequent complication of otitis media is hearing loss, which may result in speech and learning difficulties. Oral antimicrobial agents--notably ampicillin, amoxicillin, amoxicillin-clavulanate, cefaclor, cefuroxime axetil, bacampicillin, cyclacillin, erythromycin ethylsuccinate-sulfisoxazole, cefixime, and trimethoprim-sulfamethoxazole--are the mainstay of treatment. Selection of the agent should be based primarily on its spectrum of activity against Streptococcus pneumoniae and Haemophilus influenzae. Other considerations include the presence of beta-lactamase-producing strains of H. influenzae and Branhamella catarrhalis, adverse effects, cost, and compliance. In cases of recurrent otitis media, antimicrobial prophylaxis or surgery may be indicated. Chronic otitis media with effusion may be treated with oral antimicrobials, but surgery may also be necessary. Chronic suppurative otitis media often requires hospitalization and intravenous antimicrobial therapy with agents effective against Pseudomonas aeruginosa. Oral antimicrobial agents represent the treatment of choice for otitis media, but such therapy addresses only one of the several etiologic factors identified.