Contrast-induced acute kidney injury (CI-AKI) is a common complication in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI), particularly in the elderly who are more vulnerable due to renal impairment, comorbidities, malnutrition, and chronic inflammation. The hemoglobin, albumin, lymphocyte, and platelet (HALP) score has been proposed as a biomarker reflecting nutritional and inflammatory status, but its role in predicting CI-AKI in elderly STEMI patients is unclear. This retrospective study included 588 elderly (≥65 years) STEMI patients treated with pPCI between August 2019 and December 2024. CI-AKI occurred in 70 patients (11.9%), who were older and had higher rates of diabetes mellitus (DM), hypertension, and chronic kidney disease, along with lower glomerular filtration rate (GFR), left ventricular ejection fraction (LVEF), and HALP score. The mean HALP score was significantly lower in patients with CI-AKI (2.68 [2.33-3.32] vs 3.85 [2.68-5.37], P < .001). In multivariate analysis, older age, DM, lower LVEF, higher contrast volume, and lower HALP score independently predicted CI-AKI. A HALP score <2.7 predicted CI-AKI with 75% sensitivity and 55% specificity (Area Under the Curve: 0.698). The HALP score provides an accessible, independent predictor of CI-AKI in elderly STEMI patients, enabling improved early risk stratification.