Infections of the oral and maxillofacial region are one of the most common conditions for which a patient presents to a maxillofacial surgeons. Although these infections can arise from a variety of source, dental disease is the most common etiology. So, odontogenic infection are frequently encountered in the practice of oral and maxillofacial surgery. These infections often respond to antimicrobial chemotherapy or surgical intervention, such as extraction of teeth, incision and drainage through clinical features. But, odontogenic infections have the potential to spread via the fascial spaces in the head and neck region, and, they spread to cavernous sinus, deep musculofascial space and other vital structure. We have undertaken clinical studies on infections in the oral and maxillofacial regions by analyzing retrospectively hospitalized patients in the Dept. of Oral and Maxillofacial Surgery, Chonbuk National University Hospital past 5 years from 2000 to 2004. And, the patients’age, sex, medical history, causes of the infection, surgical intervention, and other clinical parameters were reviewed.The obtained results were as follows :1. The most frequent cause of oral and maxillofacial infection was odontogenic. And in the odontogenic cause, dental caries was the most common cause (47.2%).2. The most common fascial space involved was the submandibular space (15.7%), followed by the buccal space (14.8%).3. 60.4% of all patients required surgical drainage of the abscess, endodontic treatment or tooth extraction or periodontal treatment with drainage.4. The most causative organism isolated from the pus culture were streptococcus viridans (53.9%).5. Underlying medical problems were found in 136 patients (41.9%), the most common being hypertension (27.9%) and diabetes (14.7%).