Abstract: AIM: To determine the actual status of renal function in acute coronary syndrome( ACS) patients with normal serum creatinine after percutanous coronary intervention( PCI) and to explore the impact of mild renal abnormalities( RA) on adverse clinic outcomes of ACS patients after PCI. METHODS: Two hundred and eight ACS patients with normal serum creatinine following PCI were divided into three groups based on estimated glomerular filtration rate( e GFR) : Group I with e GFR 60-89 ml /( min·1. 73 m2)( mild RA group),Group Ⅱ with e GFR 30-59 ml/( min·1. 73 m2)( moderate RA group) and Group III with e GFR ≥90 ml /( min·1. 73 m2)( non-RA group). Clinical characteristics and clinical outcomes were evaluated in different groups and independent risk factors that may affect major adverse cardiac and cerebrovascular events( MACCE) were investigated. RESULTS: All-cause mortality and total incidence of MACCE in mild RA group and in moderate RA group were obviously higher than those in non-RA group( P < 0. 05). Logistic regression analysis found that age and left ventricular ejection fraction( LVEF) were independent risk factors of adverse outcomes in patients with ACS after PCI( P < 0. 05).CONCLUSION: Mild to moderate renal abnormalities is common in ACS patients with normal serum creatinine but are not independent risk factors for poor prognosis.