Abstract Background Beneficial effects of overweight and obesity on mortality after acute myocardial infarction (AMI) have been described as “Body Mass Index (BMI) paradox”. However, the effects of BMI is still on debate. We analyzed the association between BMI and 1-year major cardiocerebrovascular events (MACCE) after AMI. Methods and findings Among 13,104 AMI patients registered in an Institute of Health in Korea between November 2011 and December 2015, 10,568 patients who eligible for this study were classified into 3 groups according to BMI (Group I; <22 kg/m2, 22 ≤ Group II <26 kg/m2, Group III; ≥26 kg/m2). The primary end point was a composite of cardiac death (CD), myocardial infarction (MI), target vessel revascularization (TVR), and cerebrovascular events at 1 year. Over the median follow-up of 12 months, the composite of primary end point occurred more frequently in the Group I patients than in the Group III patients (primary endpoint: adjusted hazard ratio [aHR], 1.290; 95% confidence interval [CI] 1.024 to 1.625, p=0.031). Especially, cardiac death in MACCE components played a major role in this effect (aHR, 1.548; 95% confidence interval [CI] 1.128 to 2.124, p=0.007). Conclusions Higher BMI appeared to be good prognostic factor on 1-year MACCE after AMI. This result suggests that higher BMI or obesity might confer a protective advantage over the life-quality after AMI. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Research of Korea Centers for Disease Control and Prevention and the Korea Health Technology R&D Project, Ministry of Health & Welfare (HI13C1527), Republic of Korea.