Introduction: Coronary collateral circulation (CCC) is an adaptive response to chronic myocardial ischemia. The monocyte to high-density lipoprotein cholesterol ratio (MHR) has been reported as a new predictor and prognostic indicator of cardiovascular diseases. Objective: In this retrospective study, we aimed to investigate the association between MHR and CCC in stable coronary artery disease (CAD). Materials and Methods: A total of 355 consecutive patients who were admitted to our hospital for coronary angiography with stable angina pectoris with ≥90% stenosis were enrolled into the study. The CCC was graded using the Rentrop Classification: Grade 0-1–2-3. Results: MHR (12.5 ± 4.5 vs. 16.4 ± 5.7, P < 0.01) is significantly higher in the well CCC group than in the poor CCC group. We demonstrated that MHR levels are significantly related with the Rentrop classification of CCC. In the Rentrop III group, the MHR value was significantly higher (P < 0.01) than the Rentrop-0, Rentrop-I, and Rentrop-II group. In the Rentrop II group, the MHR value was significantly higher (p<0.01) than in the group with Rentrop-0 and Rentrop-I. This study showed that, in stable CAD, MHR levels are significantly higher in patients with good CCC than in those with poor CCC. Conclusion: MHR may serve as an independent predictor of good CCC in patients with ≥90% coronary stenosis. Limitations: This study is subject to the limitations inherent to a retrospective study, and the sample size in our study is relatively small.