Background: Optimal therapy in ST-elevation myocardial infarction (STEMI) patients with extreme age is still a challenge. The presence of comorbidities and multiorgan dysfunction simultaneously increases the risk of ischemia and bleeding. Unfortunately, there are no adequate data for the benefit and reliability of the treatment in elderly patients. Case Summary: We report a case of a 103-year-old patient with substernal chest pain 6 hours before admission. His medical history was unremarkable. The physical examination revealed irregularly irregular pulse. An electrocardiogram showed atrial fibrillation with a moderate ventricular response with ST-elevation and Q waves in inferior lead. The patient was treated conservatively with dual antiplatelet aspirin and clopidogrel, and anticoagulated with fondaparinux. Although medical management was carried out because of family concerns, the best choice of therapy for STEMI patients of extreme ages was still a question. Discussion: Current practice guidelines recommend primary percutaneous coronary intervention as therapy of choice in STEMI patients with no upper age limit, and to start dual antiplatelet therapy using aspirin and a P2Y12 receptor blocker in all patients including the elderly. In a patient with atrial fibrillation, a shorter duration of dual antiplatelet therapy is recommended. Data regarding reperfusion therapy with the best level of efficacy and safety in this group is limited. Trials comparing various treatment strategies with oral anticoagulants are designed to investigate the safety, rather than efficacy. Another option to use single antiplatelet therapy to minimize bleeding risk still has limited data.