Background: Major Adverse Cardiovascular Events (MACE) are believed to have very low in Chronic Coronary Syndrome (CCS) patients who have undergone percutaneous coronary intervention (PCI). Endothelin-1 had been considered as pro inflammatory biomarker and suggested as a novel prognostic indicator in CCS. Objective: To prove Endothelin- 1 as predictor of MACE within 1-year evaluation in CCS patients undergoing PCI. Methods: Analytic observational study with cohort design. The sample were CCS patients whom performed PCI. Endotelin-1 levels were checked before patient undergone PCI. Occurrences of MACE observed within 1 year. The comparison between normally distributed continuous data was performed with T-test, Mann–Whitney test was used for not normally distributed. Comparison between categorical data was performed with the Chi-square test. Cut-off point of Endothelin-1 levels to predict MACE analyzed by Receiver Operating Characteristics (ROC). Results: Subject of this study were 63 patients. Six patients experienced MACE within 1 year (9.5%) and 57 patients were included in No MACE group (90.5%). Mann Whitney T test showed there were significance differences in Endothelin-1 levels from the two groups (p=0.022). The ROC curve showed cut off point the Endothelin-1 is 4.07 ng/dl with a sensitivity of 83.3%, specificity of 75.4% and accuracy of 76.2%. Based on the AUC value and the accuracy of this study, Endothelin-1 was able to detect MACE within 1 year of follow-up. Conclusions: Endothelin-1 can be used as predictor of MACE within 1year evaluation in CCS patients undergoing coronary intervention. Background: Major Adverse Cardiovascular Events (MACE) are believed to have very low in Chronic Coronary Syndrome (CCS) patients who have undergone percutaneous coronary intervention (PCI). Endothelin-1 had been considered as pro inflammatory biomarker and suggested as a novel prognostic indicator in CCS. Objective: To prove Endothelin- 1 as predictor of MACE within 1-year evaluation in CCS patients undergoing PCI. Methods: Analytic observational study with cohort design. The sample were CCS patients whom performed PCI. Endotelin-1 levels were checked before patient undergone PCI. Occurrences of MACE observed within 1 year. The comparison between normally distributed continuous data was performed with T-test, Mann–Whitney test was used for not normally distributed. Comparison between categorical data was performed with the Chi-square test. Cut-off point of Endothelin-1 levels to predict MACE analyzed by Receiver Operating Characteristics (ROC). Results: Subject of this study were 63 patients. Six patients experienced MACE within 1 year (9.5%) and 57 patients were included in No MACE group (90.5%). Mann Whitney T test showed there were significance differences in Endothelin-1 levels from the two groups (p=0.022). The ROC curve showed cut off point the Endothelin-1 is 4.07 ng/dl with a sensitivity of 83.3%, specificity of 75.4% and accuracy of 76.2%. Based on the AUC value and the accuracy of this study, Endothelin-1 was able to detect MACE within 1 year of follow-up. Conclusions: Endothelin-1 can be used as predictor of MACE within 1year evaluation in CCS patients undergoing coronary intervention.