The incidence of deep neck infection has been reduced by modern antibiotic therapy. Life-threatening deep neck infection of odontogenic or upper airway origin may extend to the thorax. Early diagnosis, administration of the potent antibiotics, and complete debridement and drainage are essential to improve the chances for survival in these very ill patients. We report two cases of deep neck infection which were complicated by thoracic infection such as mediastinitis, pericarditis, and empyema as a result of descending infection.