Objectives <p>Acute Coronary Syndromes (ACS), which present with ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP), remain a major cause of mortality worldwide.</p> Background <p>This study investigates the prognostic value of the lactate/albumin ratio (LAR) in predicting 30-day mortality in ACS patients.</p> Methods <p>This retrospective study included 475 patients admitted to the emergency department between January 1, 2023 and December 31, 2023 and diagnosed with ACS. LAR values were calculated at admission and 30-day mortality outcomes were recorded. Necessary statistical analyses, including ROC analysis, were performed to determine the relationship between LAR and mortality.</p> Results <p>High LAR was significantly associated with 30-day mortality in STEMI and NSTEMI patients, and ROC analysis confirmed its discriminatory power (AUC = 0.667, p &lt; 0.05). However, this association was not observed in UAP patients.</p> Conclusion <p>By integrating markers of systemic hypoperfusion and inflammation, LAR is emerging as a reliable and accessible predictor of short-term mortality in patients with STEMI and NSTEMI. However, its prognostic utility in UAP cases appears limited and warrants further investigation. These findings emphasize the clinical importance of LAR in predicting 30-day mortality in patients with STEMI and NSTEMI.</p>