Objective: Automated external defibrillators (AEDs) have been installed for use on out-of-hospital cardiac arrest (OHCA) patients in Korea. However, there are very few cases in which the AED was used before the 119 paramedics arrived in cardiac arrest patients. This study investigated whether the locations of the AED in Korea were appropriate. Methods: This study analyzed the locations of OHCA patients, AED installations, and the number of OHCA patients within a 100-m grid around the AEDs in public and residential areas by province. The information on acute cardiac arrest patients was obtained from the original data of the Korea Disease Control and Prevention Agency. The installation of AEDs is registered with the National Emergency Medical Center. Results: The number of OHCA patients in public and residential areas was 28,434 and 95,713, respectively, and the number of installed AEDs in these locations was 15,387 and 11,420, respectively. The number of OHCA patients per AED was 1.8 in public areas and 8.4 in residential areas, and there were significant differences by province (P<0.001). The percentage of OHCA patients within the 100-m grid around the AEDs was 21.9% and 23.1% in public and residential areas, respectively (P<0.001). Conclusion There were significant differences in the AED placement locations in public and residential areas by province. In addition, the percentage of OHCA patients within a 100-m grid around AED was only 22.9%, indicating that the number of AEDs was insufficient. Efforts to enhance the AED placements and monitoring are needed to resolve the regional deviations.