Background: Activation of monocytes and lower high-density lipoprotein (HDL) levels accelerate atherosclerosis. The monocyte-to-HDL ratio (MHR) and the coronary artery disease-reporting and data system (CAD-RADS) score are recognized as proper indicators of the atherosclerotic process. Objectives: This study aimed to investigate the relationship between the CAD-RADS score and the left ventricular mass (LVM) and MHR and to evaluate the role of MHR as a predictive marker for the CAD-RADS score. Methods: In this study, the data of 160 patients, who underwent coronary computed tomography angiography (CCTA) for cardiac assessment in our radiology unit between January 2019 and January 2021, were collected and evaluated retrospectively. The CAD-RADS score, LVM, and MHR were calculated for the patients. Patients and Methods: The multivariate analysis showed independent relationships between CAD-RADS scores and high-sensitive C-reactive protein (hs-CRP) (β = 407, P < 0.001), MHR (β = 351, P < 0.001), age (β = 0.254, P < 0.001), male sex (β = 0.179, P < 0.001), and diabetes mellitus (β = 0.122, P = 0.008). The cutoff values of MHR (9.4 for CAD-RADS-1, 11.5 for CAD-RADS-2, 12.8 for CAD-RADS-3, and 14.0 for CAD-RADS-4) showed high sensitivity and specificity for the CAD-RADS scores. Conclusion: Based on the results, MHR may be associated with the CAD-RADS score and increased LVM. As an inexpensive and reliable test, MHR may be useful for the early diagnosis and follow-up of atherosclerotic heart diseases.