The rise of medical knowledge and awareness of the importance of dental and stomatognathic system increase the patients who visit dental emergency room. The chief complaints of patients who visited the emergency room varies from a pain, trauma, hemorrhag. The purpose of this study was to classify dental emergency patients by chief complaint and to analyze in indiviual group and to provide more effective emergency dental care. This study was carried out with 1129 patients visiting emergency room of the dankook university dental hospital from 7/2011 to 6/2012. Dental emergency patients was classified trauma, pain, hemorrhage group by chief complaint and studied mothly, the day of the week, time, age distribution and cause of the individual group. The chief complaint of visiting emergency room were trauma 660 people (58.5%), pain 347 people (30.7%), hemorrhage 96 (8.5%), other 26 patients (2.3%). The monthly distribution was observed in May (12.8%), March (10.5%), September (10.2%). The trauma patients were frequent in the spring and early summer but painful patients visited in September (12.7%) and May (11.8%) in March (11.2%). The peak age group was 20 to 29 years(20.9%), followed by 0 to 9 years(19.4%), 40 to 49years (15.2%,). In trauma group the peak age was under the age of 10 (31.7%), followed by 10 to 19 years (18.8%), 20 to 29 years (17.1%) . However, in pain group, peak age was 20 to 29 years (26.8%) followed by 40 to 49 years(21.3%), 30 to 39 years (19.6 %). The most common cause of trauma were subluxation(16.5%), laceration13.7%), uncomplicated crown fracture(12.05%) and in pain group was pulpal origin(46.1%), followed by periodontal origin( 20.7%), post op pain(8.9%). Undefined pain or neuralgia were 7.9%. The most common cause of hemorrhage was post extraction( 66.7%), post operation(16.7%), spontaneous bleeding due to periodontitis(12.5%). In conclusion, the trauma, pain were different in monthly distribution and the peak age of patients. Dental emergeny doctor should understand pattern of indiviual emergency group and perform proper diagnosis and treatment for more effective emergency care.