This study evaluates the association between the Intermountain Risk Score (IMRS) and coronary artery ectasia (CAE) to determine its predictive value. A retrospective study was conducted at a tertiary hospital from January 2019 to January 2024. A total of 446 patients (226 with CAE, 220 controls) were included. Clinical, laboratory, and angiographic data were analyzed. IMRS was calculated based on routine demographic and laboratory parameters. Statistical analyses included logistic regression and receiver operating characteristic (ROC) curve analysis. Patients with CAE had significantly higher IMRS scores (p = 0.011) and were more likely to fall into high-risk IMRS categories (p = 0.002). Smoking (HR: 3.744, p = 0.045), mean corpuscular volume (HR: 1.105, p = 0.019), and IMRS color category (HR: 5.255, p = 0.016) were independent predictors. ROC analysis showed an AUC of 0.617 for IMRS score and 0.627 for IMRS color category. IMRS is a significant predictor of CAE and may serve as a practical risk stratification tool. Higher-risk patients could benefit from closer monitoring and targeted interventions. Further validation in prospective studies is needed.