Objective: To evaluate the performance of European system for cardiac operative risk evaluation(EuroSCORE)Ⅱ and the Society of Thoracic Surgeons(STS) score in patients with infective endocarditis(IE) undergoing cardiac surgery. Methods: Data were retrospectively collected from adult patients undergoing cardiac surgery for IE between July 2012 and March 2016 in our hospital. EuroSCOREⅡ and STS score were calculated. The discrimination and calibration of these two scoring system were assessed by receiver-operating characteristic(ROC) curve analysis and Hosmer-Lemeshow goodness-of-fit test. According to the EuroSCOREⅡ, patients were divided into the low risk group(<3%), the medium risk group(3%~6%) and the high risk group(≥6%). Differences in prognosis among these three groups were compared. Results: Among 80 IE patients undergoing cardiac surgery, 3 patients(3.75%) died in-hospital and total 6 deaths(7.5%) were observed during follow-up. The area under the ROC curve(AUC) for the EuroSCOREⅡ, STS, and combination of them was 0.836, 0.833, and 0.846 to predict late mortality respectively; 0.946, 0.980, and 0.980 to predict in-hospital mortality respectively, which indicated good discriminative power. Hosmer-Lemeshow goodness-of-fit test showed significant P-values(P>0.05) indicating good calibration and accuracy. The predictive in-hospital mortality was similar to actual mortality in the high risk group(11.8% vs. 10.3%, P=0.358), and significantly higher than that in the low risk and medium groups(P<0.01). The predictive late mortality was similar to actual mortality in the medium risk group(4.1% vs. 4.2%, P=0.718), whereas was underestimated in the high risk group(11.8% vs. 17.2%，P<0.05) and overrated in the low risk group(1.9% vs. 0%，P<0.01). Conclusion: Both EuroSCOREⅡ and STS scoring system can satisfactorily predict in-hospital mortality and late mortality in patients with IE undergoing cardiac surgery.