Long-term incremental prognostic value of renal function over coronary artery calcium score (CACS) in symptomatic patients without known coronary artery disease (CAD) is unclear. The objective of this study was to examine additive prognostic value of renal function over CACS in patients with acute chest pain suspected of CAD. Renal function and CACS were assessed in patients without known CAD who presented to the emergency department with chest pain from 2005 to 2008. Renal function was assessed using estimated glomerular filtration rate (eGFR), and chronic kidney disease (CKD) was defined as eGFR < 60 mL/min/1.73 m². A total of 949 patients (804 non-CKD and 145 CKD, age 54 ± 13 years) were included. During the follow-up period of up to 5.3 years, major adverse cardiac events (MACE) occurred in 5.7 % of patients (19 cardiac deaths, 6 myocardial infarction and 29 late coronary revascularization). Annualized MACE rate was higher in patients in higher CACS categories with and without CKD (p = 0.011 and p < 0.001 respectively). In multivariate logistic regression analysis, CACS categories (CACS 1–100: HR 3.17, p = 0.005; CACS 101–400: HR 7.68, p < 0.001; CACS > 400: HR 8.88, p < 0.001) and CKD (HR 10.18, p < 0.001) were independent predictors for MACE. Both adding renal function and CACS significantly improved the overall predictive performance (p < 0.001 for global Chi square increase) from Framingham risk categories or thrombolysis in myocardial infarction (TIMI) risk score. Both CACS and renal function were independent predictors for future cardiac events and provided additive prognostic value to each other and over either Framingham risk categories or TIMI risk score.