Background/Objectives: Despite the contemporary management of ST segment elevation myocardial infarction (STEMI) patients, in-hospital mortality rates remain considerable. Therefore, the assessment of in-hospital mortality risk of patients with STEMI has a major role in terms of disease course. R2CHADS2, R2CHA2DS2-VASc, and R2CHA2DS2-VA scores are potential candidate for the prediction of in-hospital mortality in STEMI patients. This study aims to determine the association between R2CHADS2, R2CHA2DS2-VASc, and R2CHA2DS2-VA scores and in-hospital mortality in patients with STEMI who have undergone primary percutaneous coronary intervention (p-PCI). Methods: A total of 857 consecutive patients diagnosed with STEMI who were admitted to our hospital and treated with p-PCI were included in our study. Results: The mean age of the study population was 58 +/- 11 years and the population was predominantly male (78.5%). Patients in the in-hospital mortality group tended to be older compared to those who survived (65 +/- 12 and 57 +/- 11 years, respectively, p < 0.001), while gender showed no significant difference. Multivariable regression models showed that left ventricular ejection fraction, eGFR, R2CHADS2 (OR 2.21, 95% CI 1.38-3.54, p = 0.001), R2CHA2DS2-VASc (OR 1.91, 95% CI 1.30-2.80, p = 0.001), and R2CHA2DS2-VA (OR 1.97, 95% CI 1.345-2.910, p = 0.001) scores were independent predictors of in-hospital mortality. Conclusions: The R2CHADS2, R2CHA2DS2-VASc, and R2CHA2DS2-VA scores demonstrate strong predictive ability for in-hospital mortality in STEMI patients, and their non-negligible advantages support their implementation in clinical practice.