The sensitivity and specificity of the acoustic otoscope in detecting middle ear effusion (MEE) was determined for 200 children. Based upon results from otoscopy, tympanometry, pure tone audiometry, and myringotomy, 100 of the children (175 ears) had MEE. The remaining 100 (200 ears) had no MEE. Using acoustic otoscope reflectivity (AOR) units 4 through 9 to indicate pathologic ears, its sensitivity and specificity were found to be 93.14% and 83%, respectively. These findings led to the conclusion that the acoustic otoscope may provide a simple and cost-effective way of detecting MEE in children. Suggestions are provided for improving the effectiveness of this new device as a clinical tool.