One of the major missions of the Taiwan Society of Cardiology is to publish practice guidelines that are suitable for local use in Taiwan. The ultimate purpose is to continuously improve cardiovascular health care from the implementation of the recommendations in the guidelines. Despite recent improvement of medical care, patients with ST-segment elevation myocardial infarction (STEMI) still carry a high morbidity and mortality. There have been many changes in the concepts of STEMI diagnosis and treatment in recent years. The 2020 focused update of the 2012 guidelines of the Taiwan Society of Cardiology for the management of STEMI is an amendment of the 2012 guidelines based on the newest published scientific data. The recommendations in this focused update provide the diagnosis and treatment strategy for STEMI that should be generally implemented in Taiwan. Nevertheless, guidelines never completely replace clinical judgment and medical decision still should be determined individually.