Acute Otitis Media (AOM) is a viral and/or bacterial infection of the middle ear and represents the most common childhood infection for which antibiotics are prescribed in the United States. Timely and accurate diagnosis and management of AOM can have significant individual and public health consequences. The 2001 AHRQ evidence report on the management of AOM analyzed the evidence on the initial management of uncomplicated AOM in children, focusing on the natural history of the disease and the use of antibiotics in management. Although the 2001 report provided valuable analysis of the literature on the management of uncomplicated AOM in children, it did not address issues related to diagnostic accuracy and precision, management of AOM in specific subgroups of children, or the impact of immunization with Heptavalent Pneumococcal Conjugate Vaccine (PCV7) on the microbiology of AOM, recommended for widespread use in 2000. Additionally, new trials of treatment continue to be published. The purpose of this current AHRQ evidence report is to examine and analyze the evidence on three broad areas of inquiry: 1) accuracy and consistency of the clinical diagnosis of AOM, 2) the impact of PCV7 on AOM microbial epidemiology, and 3) the comparative effectiveness of different treatment options for uncomplicated AOM in average risk children and in children with recurrent (defined as three or more episodes in six months or four or more episodes within 12 months) or persistent AOM. The American Academy of Pediatrics, the nominating organization, proposed six key questions aimed at assessing the comparative efficacy of interventions to treat uncomplicated and recurrent AOM in terms of treatment success, the safety of such treatments, and the effect on children in specific subgroups. In conjunction with a technical expert panel we refined these questions: I. Diagnosis of AOM: What are the operating characteristics (sensitivity, specificity, and likelihood ratios) of clinical symptoms and otoscopic findings (such as bulging tympanic membrane), both individual and composite, to diagnose uncomplicated AOM and to distinguish it from otitis media with effusion (OME)? II. What has been the impact of the Pneumococcal Heptavalent Immunization (PCV7) on AOM microbial epidemiology (including acute mastoiditis and suppurative complications), with respect to both the organisms associated with AOM and the patterns of antimicrobial resistance? III. What is the comparative effectiveness of different treatment options for treating uncomplicated AOM in average risk children? IV. What is the comparative effectiveness of different management options for recurrent otitis media (uncomplicated) and persistent otitis media or relapse of AOM? V. Do treatment outcomes in Key Question3 (KQ3) and KQ4 differ by characteristics of the condition (AOM), patient, environment, and/or health care delivery system, including but not limited to the following: A. Laterality, i.e., unilateral vs. bilateral; B. Otorrhea or perforation; C. AOM severity, i.e., as defined as defined by the AAFP/AAP AOM Guideline (2004); D. Comorbidities, e.g., asthma; E. Age groups, e.g., less than 4 weeks, 4weeks to less than 6 months, 6mos-less than 2 years, 2-5 years; F. Race; G. Ethnicity; H. Day care attendance? VI. What adverse effects have been observed for the treatments whose outcomes are addressed in KQ III and KQ IV?