OBJECTIVE: Coronary artery calcification is a cornerstone marker for coronary atherosclerosis. Therefore, the calculation of the coronary artery calcium score has become a routine method in diagnosing coronary artery disease in recent years. Monocyte to high-density lipoprotein cholesterol ratio reflects proatherogenic and antiatherogenic balance, and this ratio is associated with coronary atherosclerosis and cardiovascular events. This study aimed to investigate the value of monocyte to high-densitylipoprotein cholesterol ratio in predicting coronary atherosclerosis, which coronary artery calcium score determines. METHODS: A total of 276 patients with chest pain who underwent coronary computed tomography angiography were enrolled in the study. The patients were divided into 3 groups according to coronary artery calcium score [coronary artery calcium score=0 for very low risk (n=121), coronary artery calcium score=1-99 for low risk (n=100), coronary artery calcium score ≥ 100 for moderate-high risk (n=55)]. The monocyte to high-density lipoprotein cholesterol ratio, neutrophil-to-lymphocyte ratio, systemic immune-inflammation index, and plateletto-lymphocyte ratio were calculated from venous blood samples. RESULTS: Monocyte to high-density lipoprotein cholesterol ratio values were significantly higher in patients with moderate-high coronary artery calcium score (1.29 ± 0.59 vs 1.41 ± 0.56 vs 1.56 ± 0.58, P =.009). However, there were no differences between the groups in terms of other inflammatory markers (neutrophil-to-lymphocyte ratio, systemic immune-inflammation index, and platelet-to-lymphocyte ratio). Age (odds ratio: 1.178; 95% CI: 1.107-1.253; P < .001), dyslipidemia (odds ratio: 14.252; 95% CI: 5.459-37.211; P <.001), smoking (odds ratio: 2.893; 95% CI: 1.317-6.358; P=.008), and monocyte to high-density lipoprotein cholesterol ratio (odds ratio: 2.082 per 1-point increase; 95% CI: 1.016-4.268; P=.045) were independent predictors of coronary artery calcium score in multivariate analysis. CONCLUSION: Our data showed that high monocyte to high-density lipoprotein cholesterol ratio is significantly associated with increased coronary artery calcium score. Monocyte to highdensity lipoprotein cholesterol ratio indicates that it can be applied easily and swiftly in clinics to help predicting the coronary artery disease.