Odontogenic sinusitis is a well-recognized condition and accounts for approximately 10% to 12% of cases of maxillary sinusitis. An odontogenic source should be considered in patients with symptoms of maxillary sinusitis who give a history positive for odontogenic infection or dentoalveolar surgery or who are resistant to standard sinusitis therapy. Diagnosis usually requires a thorough dental and clinical evaluation with appropriate radiographs. Common causes of odontogenic sinusitis include dental abscesses and periodontal disease perforating the Schneidarian membrane, sinus perforations during tooth extraction, or irritation and secondary infection caused by intra-antral foreign bodies. The typical odontogenic infection is now considered to be a mixed aerobic-anaerobic infection, with the latter outnumbering the aerobic species involved. Most common organisms include anaerobic streptococci, Bacteroides, Proteus, and Coliform bacilli. Typical treatment of atraumatic odontogenic sinusitis is a 3- to 4- week trial of antibiotic therapy with adequate oral and sinus flora coverage. When indicated, surgical removal of the offending odontogenic foreign body (primary or delayed) or treatment of the odontogenic pathologic conditions combined with medical therapy is usually sufficient to cause resolution of symptoms. If an oroantral communication is suspected, prompt surgical management is recommended to reduce the likelihood of causing chronic sinus disease.