Purpose: Poisoning is a major health problem for the elderly, and poisoning can cause fatal side effects. However, the characteristics and clinical features of elderly patients with acute poisoning have not been well studied in the previous domestic research. So, we tried to analyze the clinical characteristics and toxic substances of the patients who were 65 years old or older and who were admitted to the regional emergency medical center due to acute poisoning. Methods: We retrospectively reviewed the medical records and poisoning protocols of the patients who were 65 years of age or older and who had with acute poisoning and who visited the ED in our emergency center from January 2005 to December 2009. We collected the demographic information, the gender, the underlying diseases, the causes and toxic substances, the initial presentation, the treatment and the outcomes. Results: A total of 2179 poisoned patients visited the hospital during 5 years, and among them 244 were 65 years of age or older (11.2%). The mean age was $75.6{pm}6.9$ years and the male:female ratio was 1:1.7. The most common cause of poisoning was suicide (73.4%) and the most common source of poisonous substances was their own drugs. Of the substances used for poisoning, benzodiazepine was the most common drug (25.8%), followed by sedatives other than benzodiazepine (25.4%), insecticide (12.7%), chemical agents (12.3%) and herbicides (8.2%). The most common initial presentation was mental change (64.8%). When comparing the factors between the three elderly groups, there was no difference in gender, the cause, the substances and the underlying disease. The outcomes of treatment included ICU admission (56.1%), a good condition at discharge (12.7%) and admission to a general ward (12.7%). The overall mortality rate was 10.2% for the elderly patients. Conclusion: In this Korean study, unlike the foreign studies, the most common cause of poisoning in elderly patients was intentional poisoning. The admission rate was 68.8% and mortality rate was 10.2%.