Acute sinusitis is one of the most common disease in children requiring antimicrobial treatment. The diagnosis and treatment outcomes of acute sinusitis are contradictory, and better diagnostic criteria are needed. In adults with acute maxillary sinusitis, bacterial culture results obtained from the nasal middle meatus are comparable to those obtained from sinus puncture and aspiration. In children, the presence of pathogenic bacteria (S. pneumoniae, H. influenzae or M. catarrhalis) in the nasal middle meatus during respiratory infection predicts longer duration of signs and symptoms of common cold.