Systemic inflammation and glucose metabolism are strongly associated with survival in ST-elevation myocardial infarction (STEMI) patients. Therefore, we aimed to assess whether the glucose-to-lymphocyte ratio (GLR) could be used to predict the prognosis of STEMI patients who received emergency percutaneous coronary intervention (PCI) treatment.The GLR was calculated as follows: GLR = glucose (mg/dL) / lymphocyte count (K/μL). Patients were divided into two groups according to the median GLR, with the low-GLR group (GLR <81) employed as the reference group. We used Cox proportional hazard regression analyses to determine the predictive value of clinical indicators. Kaplan‒Meier curves were used to plot survival curves for both groups. The receiver operating characteristic (ROC) curves were used to assess the predictive value of the GLR for the risk of all-cause mortality and cardiovascular mortality in STEMI patients. Meanwhile, to evaluate the predictive effectiveness of the models, we plotted the ROC curves for each model.We retrospectively analyzed 1086 newly admitted patients with STEMI who underwent emergency PCI at the First Affiliated Hospital of Kunming Medical University from June 2018 to January 2023 (mean follow-up time, M ± standard deviation (SD): 1100.66 ± 539.76 days). The results showed that high GLR was associated with increased risks of all-cause mortality (hazard ratio (HR) = 2.530, 95% CI = 1.611-3.974, p < 0.001) and cardiovascular mortality (HR = 3.859, 95% CI = 2.225-6.691, p < 0.001). The optimal GLR threshold for predicting all-cause and cardiovascular death was 79.61 (K/μL), with a ROC for all-cause death of 0.678 (95% CI: 0.625-0.732, p < 0.001), a sensitivity of 77.4%, a specificity of 51.9%, and a ROC for cardiovascular death of 0.716 (95% CI: 0.666-0.767, p < 0.001), with a sensitivity of 88.4% and a specificity of 52.1%.The GLR may potentially predict all-cause mortality and cardiovascular mortality in STEMI patients who received emergency PCI treatment. A high GLR was associated with a greater risk of all-cause mortality and cardiovascular mortality in STEMI patients.Copyright: © 2025 The Author(s). Published by IMR Press.