A regionalization strategy is a model for improving the performance of the emergency medical service (EMS) system. The regionalization strategy has goals to provide appropriate, timely, effective, and efficient EMS in a region. However, the current EMS regionalization model in Korea is insufficient to achieve these goals due to a shortage of resources in rural regions, crowded emergency departments in metropolitan regions, and non-customized and mismatched levels of emergency departments. Recently, the concept of the regionalization model has been changed from a general regionalized model to a specialty care regionalization one. For example, the trauma care system, cardiac arrest care system, stroke care system, and ST elevation myocardial infarction care system are modern regionalization strategies to improve the performance of EMS. This is a new method of customizing and matching between region-based needs and the supply of EMS. If we can implement this strategy, we can expect improved performance of regional EMS systems.