The diagnosis of acute otitis media (AOM) is made on clinical basis. The gold-standard tests are invasive. There are few studies quantifying the diagnostic power of the signs and symptoms. A sample of 300 children were analyzed to establish the diagnostic power of isolated and combinated signs and symptoms in AOM. The most important diagnostic signs were bulging, fluid level, acute perforation, and change in color of the tympanic membrane. Fever was the single symptom with statistical significance. We concluded that we can do an accurate and noninvasive AOM diagnosis using otomicroscopic findings.