Objective: To determine whether COVID‐19 may adversely affect outcome of myocardial infarction (MI) patients in Hong Kong, China. Background: The COVID‐19 pandemic has infected thousands of people and placed enormous stress on healthcare system. Apart from being an infectious disease, it may affect human behavior and healthcare resource allocation which potentially cause treatment delay in MI. Methods: This was a single center cross‐sectional observational study. From November 1, 2019 to March 31, 2020, we compared outcome of patients admitted for acute ST‐elevation MI (STEMI) and non‐ST elevation MI (NSTEMI) before (group 1) and after (group 2) January 25, 2020 which was the date when Hong Kong hospitals launched emergency response measures to combat COVID‐19. Results: There was a reduction in daily emergency room attendance since January 25, 2020 (group 1,327/day vs. group 2,231/day) and 149 patients with diagnosis of MI were included into analysis (group 1 N = 85 vs. group 2 N = 64). For STEMI, patients in group 2 tended to have longer symptom‐to‐first medical contact time and more presented out of revascularization window (group 1 27.8 vs. group 2 33%). The primary composite outcome of in‐hospital death, cardiogenic shock, sustained ventricular tachycardia or fibrillation (VT/VF) and use of mechanical circulatory support (MCS) was significantly worse in group 2 (14.1 vs. 29.7%, p = .02). Conclusions: More MI patients during COVID‐19 outbreak had complicated in‐hospital course and worse outcomes. Besides direct infectious complications, cardiology community has to acknowledge the indirect effect of communicable disease on our patients and system of care.