Backgrounds: The relation between body-mass index (BMI) and waist-to-hip ratio (WHR) to clinical outcomes in patients with ST-segment elevation acute myocardial infarction (MI) has not been well described. Methods: As part of the Korean Acute MI Registry, we enrolled 3734 eligible patients who were diagnosed with ST-segment elevation acute MI. The study population was categorized by BMI (into 4 groups according to the World Health Organization classification for the Asian population), and WHR (into 2 sets of 4 groups, one for men and another for women, based on the INTERHEART study). Baseline characteristics, and rates of mortality and adverse events were analyzed and compared among the BMI and WHR categories. The mean follow-up duration was 438짹162 days. Results: In the BMI category, underweight vs. other weight groups were older, more likely to present with heart failure, and underwent guideline-based treatments less frequently. In the WHR category, the reverse trends were shown in those factors, but treatments had no significant difference according to WHR. The highest rate of mortality was observed in patients with the lowest BMI and in those with the highest WHR. In adjusted model, the highest WHR [Hazard ratio (HR), 4.25; 95% Confidence interval (CI), 1.69 to 8.21; p=0.002] and underweight (HR, 3.31; 95% CI, 1.57 to 5.12; p=0.009) within two anthropometric indices were remained as risk factors for mortality. Conclusions: The risk of short-term mortality appears to be increased by underweight and central obesity after ST-elevation acute MI in same population, which may be partly explained by clinical confounders demonstrating different results between BMI and WHR.