Objectives: This study aims to investigate the utility of Osaka Prognostic Score (OPS) in predicting all-cause mortality in patients under -going endovascular treatment (EVT) for iliac artery stenosis. Patients and methods: Between January 2015 and December 2020, a total of 183 patients (165 males, 18 females; mean age: 61.0+/-8.8 years; range, 36 to 92 years) who underwent EVT for iliac artery stenosis were retrospectively analyzed. The patients were categorized into four OPS groups (0-3). Mortality outcomes were confirmed using national death records. The OPS performance was compared with the Glasgow Prognostic Score (GPS) and the Systemic Inflammation Score (SIS) using receiver operating characteristic (ROC) analysis. Multivariate logistic regression was used to assess independent predictors of mortality. Results: Overall mortality was 26.8%. Higher OPS scores were significantly associated with increased mortality (OPS 0: 14.1%, OPS 3: 60%, p<0.001). The OPS remained an independent predictor of all-cause mortality (odds ratio [OR]=3.452, 95% confidence interval [CI]: 1.342-8.878, p=0.010). The OPS >=2 was also associated with higher rates of myocardial infarction and restenosis. The OPS demonstrated superior prognostic performance (area under curve [AUC]=0.682) compared to GPS (AUC=0.671) and SIS (AUC=0.571). Conclusion: The OPS independently predicts all-cause mortality after EVT for iliac artery stenosis and outperforms other inflammation-based scores. Its simplicity and reliance on routine biomarkers make it a practical tool for risk stratification in peripheral artery disease.