The spectrum of otitis media includes acute and chronic forms, each of which can be either suppurative of nonsuppurative. In the usual clinical setting distinctions between these several forms can be difficult. Determination of accurate incidence figures is impeded by the unavailability of universally accepted diagnostic criteria. Risk factors include season of the year, genetic factors, race, preceding respiratory tract infections, cleft palate, and others. The effect of household size and allergy are uncertain. The most common infecting organisms are Streptococcus pneumoniae and Hemophilus influenzae, although in a significant number of cases either the fluid is nonpathogenic or no organisms can be isolated. The effects of several therapies are reviewed, including antibiotics, myringotomy, steroids, and middle-ear ventilating tubes.