Introduction: The obesity paradox has been observed in patients with cardiovascular disease. The goal of this study was to evaluate whether obesity has a protective effect in patients presenting with an ST elevation myocardial infarction (STEMI). Method: Using the large Nationwide Inpatient (NIS) sample database, we evaluated the mortality in patients with a STEMI based on weight categories. Results: A total of 2,161,640 STEMI patients were found in the database over age 18. We found that overweight and obesity had the lowest mortality using univariate (overweight mortality of 5% vs. obesity mortality of 6.5% vs. 10.9% for normal weights) and multivariate analyses (overweight OR: 0.52, CI: 0.43–063; p < 0.001 and obesity OR: 0.7, CI: 0.67–0.74; p < 0.001), whereas cachexia was associated with the highest mortality in the univariate (cachexia 24.5%) and multivariate (OR: 2.28, CI: 2.13–2.44; p < 0.001) analyses, followed by morbid obesity in the multivariate analysis (OR: 1.07, CI: 1.02–1.12; p = 0.004). Conclusions: We observed a partial obesity paradox in patients with a STEMI showing that overweight have the best survival rates followed by obesity. Cachexia followed by morbid obesity had the lowest survival rates.