The prognostic value of admission estimated glomerular filtration rate (eGFR) calculated by the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula for cardiovascular adverse outcomes in acute coronary syndrome (ACS) was explored. Baseline eGFR was classified as no renal dysfunction (>90 mL/min per 1.73 m(2)), borderline (90-60.1 mL/min per 1.73 m(2)), moderate (60-30.1 mL/min per 1.73 m(2)), or severe (≤30 mL/min per 1.73 m(2)) renal dysfunction. Of the 5034 patients, 3415 (67.8%) had eGFR <90. Compared to patients with an eGFR ≥60 mL/min per 1.73 m(2), patients with <60 mL/min per 1.73 m(2) were less likely to be treated with β-blockers, angiotensin-converting enzyme inhibitors, or statins, or to undergo percutaneous coronary interventions. Lower eGFR showed a stepwise association with significantly worse adverse in-hospital outcomes. The adjusted odds ratio of in-hospital death with an eGFR <30 mL/min per 1.73 m(2) was 3.1 (95% confidence interval 1.1-8.4, P = .0324), compared with an eGFR >90 mL/min per 1.73 m(2). Estimated glomerular filtration rate calculated by the new CKD-EPI is an independent predictor of major adverse cardiac outcomes in patients with ACS.