The exercise electrocardiography test (EET) is still used before coronary angiography in the diagnosis of chronic coronary syndromes. This study aimed to demonstrate the value of the combination of a positive EET with the systemic inflammatory index (SII), the plasma atherogenic index (PAI), and the monocyte/HDL-C ratio (MHR) in the determination of obstructive coronary artery disease (CAD). This single-center, retrospective study included 540 patients who underwent coronary angiography after ETT. The patients were separated into Group 1, comprising 434 patients with normal coronary arteries and non-obstructive CAD, and Group 2, including 106 with obstructive CAD. In Group 2, the patients were separated into SYNTAX ≤ 22 or ≥23. Glucose, low-density lipoprotein, white blood cells, and MHR were determined to be significantly higher in Group 2 (p < 0.05). According to the multivariate logistic regression analysis, age, gender, diabetes mellitus, and low-density lipoprotein were determined to be independent predictors of CAD. In the ROC curve analysis, a cut-off value of 12 for the MHR in the determination of obstructive CAD had a sensitivity of 60.4% and a specificity of 53.0%. The main result of this study was that a high MHR is an indicator of obstructive CAD in patients with positive EET and suspected CAD.