Background: Acute ST-elevation myocardial infarction (STEMI) demands rapid intervention, with primary percutaneous coronary intervention (PCI) playing a pivotal role. While existing risk models focus on clinical factors, the SYNTAX score assesses coronary lesion complexity. This study aimed to assess SYNTAX scores' association with short-term outcomes in STEMI patients undergoing primary PCI and compare it with SYNTAX Score II. Methods: This prospective observational study was conducted on 110 Egyptian patients diagnosed with STEMI undergoing primary PCI. Patients were evaluated based on SYNTAX scores and divided into low (≤16), intermediate (16)(17)(18)(19)(20)(21)(22), and high (>22) SYNTAX score groups. Short-term outcomes including all-cause mortality, cardiac mortality, reinfarction, and revascularization were assessed over a 1-year follow-up period. Results: Patients with higher SYNTAX scores (>31) exhibited significantly lower ejection fractions (p<0.001), longer duration of chest pain (p<0.05), higher GRACE scores (p<0.05), and increased rates of failed PCI (p=0.036) and multivessel disease (p<0.01). In-hospital mortality, all-cause mortality, and major adverse cardiac and cerebrovascular events (MACCE) during follow-up were significantly higher in patients with higher SYNTAX scores (p<0.005). Survival rates were significantly lower in patients with higher SYNTAX scores compared to lower scores (p<0.005). Conclusion: The SYNTAX score, along with its derivatives SYNTAX Score II (SSII) and Clinical SYNTAX Score (cSS), demonstrated a significant association with short-term outcomes in STEMI patients undergoing primary PCI. Higher SYNTAX scores correlated with increased rates of adverse events, emphasizing its potential utility in risk stratification.