Otitis media (OM) is the most frequently diagnosed disease in infants and young children. Large, prospective studies suggest an increase in incidence of this disease during the past 10 to 20 years, possibly reflecting a change in host and environmental risk factors for the development of OM. Good knowledge of host (intrinsic) and environmental (extrinsic) risk factors for the development of otitis media is important in identifying a child at risk for recurrent and persistent OM. This could result in primary and/or secondary prevention of OM and a decrease in complications and sequelae.