The purpose of this study is to analyze ER patient's Triage and other statistical data. The subjects were 12,618 patients who visited the ER during the year 1998. The study showed the following results; 1. The male vs female ratio was 1.3 : 1.0, the male were in the majority (56.6%), and the age range of 20-29 old was the majority (15.3). The patients who visited ER at 8-10 pm were the majority (11.5%). On Sunday the number of patients who visited the ER were 2,189, and the majority were 17.4%. On Saturday the number of patients was visited the ER were 1,944 patients the second majority (15.4%). Their traffic means : the general passenger cars (75.5%), 119 or hospital ambulance (11.3%). 2. The reasons of visiting ER were : diseases (59.2%), injuries (23.7%). The disease vs injury ratio was 100 : 69. 3. Triage : urgent 40.7%, non-urgent 38.2%, acute 17.8%, and critical 3.2%. 4. The time of waiting and staying in the ER by the Triaget: the average time was 572 minutes (9.53 hrs.). The majority of critical patients (20.5%), acute patients (24.7%) and urgent patients (21.2%) stayed 12-24 hrs., but the majority of non-emergent (27.8%) stayed not longer than one hour. 5. Treatments by the Triage : the 42.9% of critical patients, and 61.3% of acute patients, 57.5% of urgent patients were admitted. But 91.8% of the non-emergents were discharged and 4.7% was admitted. Mortality of total ER visiter were 1.7%. DAA portion was 0.86%. 26.6% of the critical patients were DAA. DAA vs DOA ratio was 1.3 : 1.0. 6. Visiting time, monthly and seasonal distribution by the Triage : the majority of critical patients (12.2%), visited 10-12 am. The majority of acute (12.9%) and urgent (11.7%) visited 4-6 pm, but the majority of non-emergents (15.1%) visited during 8-10 pm. Autumn visiter were the majority (27.6%). The percentage of non-emergent visited in Spring was 41.4% and Autumn was 41.3%. The percentage of urgents who visited in the Summer was 45.3% and the Winter was 40.4%. By clinical departments: the 48.0% of critical patients was NS. The 45.5% of acute and the 33.6% of urgent patients were IM. But the majority of non-emergent patients was PS (21.2%), and the second majority of non-emergent patients was oral Surgery (12.8%).