Abstract: Objective To investigate short- and long-term outcomes of primary percutaneous coronary intervention (PPCI) in young patients with ST-elevation myocardial infarction (STEMI). Methods From January, 2007 to January, 2017, a total of 1 647 patients with STEMI underwent PPCI at our hospital. Based on age when PPCI was performed, patients were divided into young (≤ 55 years) and middle-elderly (>55 years) groups. Retrospective analysis of short- and long-term outcomes of these two patient groups was conducted. Results The study population included 302 patients in the young group and 1 345 patients in the middle-elderly group. During the study period, the number of young patients with STEMI tended to increase annually. Compared with the middle-elderly patients, the young patients more often were male, smokers, and obese, and had a family history of coronary heart disease. However, hypertension, hyperlipidemia, diabetes, and history of previous MI occurred less frequently in the young group than in the middle-elderly group. Thirty-day mortality and incidence of major adverse cardiovascular events (MACE) also were lower in young patients. Long-term follow-up results showed that both overall and MACE-free survival were higher in young patients. Conclusion In summary, number of young patients with STEMI increased over the past decade, and these patients tended to be male, smokers, and/or obese, but had better short- and long-term outcomes. Hence, active weight loss and smoking cessation may be expected to reduce incidence of STEMI among young people.