Background Chronic kidney disease (CKD) is a common comorbidity in patients with acute coronary syndrome (ACS) and may potentially influence platelet function. Hypothesis We explored the influence of renal function on platelet reactivity to investigate whether high residual platelet reactivity (HRPR) is associated with cardiovascular events. Methods ACS patients treated with aspirin and clopidogrel were prospectively enrolled. Patients were categorized into two groups on the basis of baseline estimated glomerular filtration rate (eGFR): non-CKD (eGFR >= 60 mL/min/1.73 m(2)) and CKD (eGFR <60 mL/min/1.73 m(2)). Platelet function was measured by thromboelastography >= 5 days after maintenance dual antiplatelet therapy. Major adverse clinical events (MACEs) were collected at 1 year after discharge. Results There were 282 non-CKD patients and 212 CKD patients. A significant difference in median MA(ADP) value was observed between the two groups (15.0 mm vs. 31.3 mm, p < .001). HRPR was more prevalent in the CKD group than the non-CKD group (27.4% vs 9.6%, p < .001). At 1-year follow-up, the incidence of MACEs was significantly higher for those with both CKD and HRPR compared with those with either CKD or HRPR (37.9% vs. 18.5%, p < .001). The relationship between HRPR and MACEs was consistent across CKD strata without evidence of interaction. Adding platelet reactivity to eGFR improved the model with area under the curve increasing from 0.703 to 0.734. Conclusion In patients with ACS, the risk of HRPR increased with declining eGFR. Both CKD and HRPR were associated with MACEs at 1-year follow-up.