Acute otitis media (AOM) is the inflammation of the mucoperiostal epithelium of the middle ear with sudden onset of signs and symptoms, such as otalgia and fever. Ninety percent of all children less than two years of age experience at least one bout of AOM. Age (between six to 24 months), absence of breastfeeding in the first three months of life, ethnicity, exposure to tobacco smoke, daycare attendance, male gender, pacifier use, seasonality (fall and winter), and underlying diseases are predisposing factors. Sudden onset, presence of middle ear effusion, and acute inflammatory signs and symptoms are essential for the definitive diagnosis of AOM. Eustachian tube obstruction is the key event in the pathophysiology. Viruses and bacteria play a major role in the etiology of AOM, Streptococcus pneumoniae (40-50%), non-typable Haemophilus influenzae (30-40%), and Moraxella catarrhalis (10-15%) being the most common bacterial pathogens. Fifty percent of S. pneumoniae, more than one third of non-typable Haemophilus influenzae, and nearly all Moraxella catarrhalis strains are resistant to b-lactam antibiotics. The first step in the management of AOM should be the relief of ear pain. Observation without antibiotics is an option, that can be chosen on the case basis. If an antibiotic is to be started, the agent of choice should be high dose (80-90 mg/kg/day) amoxicillin. The physician can resort to second-line antimicrobials, such as amoxicilin-clavulanate and cephalosporins, if the clinical response is inadequate. Heptavalent pneumococcal vaccine reduces the incidence of acute otitis media, but not that of recurrences.