Objectives: We aimed to investigate the relationship between the platelet-lymphocyte ratio (PLR) and coronary collateral circulation (CCC) in patients with stable angina pectoris (SAP) and chronic total occlusion (CTO). Methods: A total of 294 patients with both SAP and CTO were classified according to their Rentrop collateral grades as either poor (Rentrop grades/0-1) or good (Rentrop grades/2-3). Results: The PLR values were significantly higher in patients with poor CCC than in those with good CCC (156.8 + 30.7 vs 132.1 + 24.4, P<0.001). In regression analysis, PLR (unit=10) [odds ratio 1.48, 95% confidence interval (CI) 1.33 -1.65; P<0.001] and high-sensitivity C-reactive protein were found to be the independent predictors of poor CCC. In receiver operator characteristic curve analysis, optimal cut-off value of PLR to predict poor CCC was found as 138.1, with 76% sensitivity and 65% specificity. Conclusion: PLR may be an important, simple, and cost effective tool predicting the degree of collateralization in patients with SAP and CTO.