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 (Synergy between percutaneous coronary intervention with taxus and cardiac surgery) 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 SSII. 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 (16-22), and high (>22) SYNTAX score groups. Short-term outcomes including all-cause mortality, cardiac mortality, reinfarction, and revascularization were assessed over a 3-month follow-up period. Results: Patients with higher SYNTAX scores (>22) 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.