Purpose: The study examined the poisoned patients' characteristics nationwide in Korea by using data from the National Emergency Department Information System (NEDIS). Methods: Among the patients' information sent to NEDIS from January 1, 2013 to December 31, 2015, the included subjects' main diagnosis in ED showed poisoning according to the 7th edition of the Korean Standard Disease Classification (KCD-7). We analyzed the patients' gender, age, initial vital signs, visit time, stay time of staying in ED, results of ED care, main diagnosis in ED, length of hospitalization, and results of hospitalization. Results: A total of 106,779 ED visits were included in the analysis. There were 55,878 males (52.3%), which was more than the number of females. The number of intentional poisoning was 49,805 (59.6%). 75,499 cases (70.8%) were discharged, and 25,858 cases (24.2%) were hospitalized. The numbers of poisoning patients per 1,000 ED visits were 14 in Chungnam and 11.9 in Jeonbuk. The most common cause of poisoning, according to the main diagnosis, was venomous animals. It was the same for hospitalized patients, and pesticide was next. Pesticide was the most common cause of mortality in ED (228 cases, 46.1%) and after hospitalization (584 cases, 54.9%). The incidence of poisoning by age group was frequent for patients in their 30s to 50s, and mortality in ED and post-hospitalization were frequent for patients in their 60s to 80s. Conclusion: This study investigated the characteristics of poisoning patients reported in the past 3 years. Pesticide poisoning had a high mortality rate for patients in ED and in-hospital. For mortality, there was a high proportion of elderly people over 60. Thus, policy and medical measures are needed to reduce this problem. Since it is difficult to identify the poison substance in detail due to nature of this study, it is necessary to build a database and monitoring system for monitoring the causative substance and enacting countermeasures.