Objective · To investigate the clinical application of serum remnant cholesterol (RC) to the assessment of patients with acute coronary syndrome (ACS). Methods · We enrolled 293 patients with stable angina (SA), 115 patients with non-hypertensive ACS, 72 patients with hypertensive ACS, 91 patients as controls, and 152 healthy controls. Levels of total cholesterol (TC), HDL- cholesterol (HDL-Ch), and LDL-Ch were measured with biochemistry method. RC was given by subtracting LDL-Ch and HDL-Ch from TC and non-HDL-Ch was given by subtracting HDL-Ch from TC. The correlations of RC with TC, LDL-Ch, HDL-Ch, and non-HDL-Ch were analyzed. ROC curves were used to analyze the application of RC, LDL-Ch, HDL-Ch, and non-HDL-Ch for differentiating SA and ACS. Results · The RC level was significantly higher in the ACS group and the hypertensive ACS group than in the SA group (P<0.05). Correlations of RC with TC, LDL-Ch, HDL-Ch, and non-HDL-Ch were statistically significant (P<0.01). The ROC curve analysis showed that RC was the best for differentiating SA and ACS, followed by non-HDL-Ch, LDL-Ch, TC, and HDL-Ch. Conclusion · Remnant cholesterol is significantly elevated in the patients with ischemic heart disease and can be used for differentiating ACS and stable angina.