Despite significant advances in imaging modalities for diagnosing coronary artery disease (CAD), there remains a need for novel diagnostic approaches with high predictive values and fewer limitations. Circulating biomarkers, including cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8), cell adhesion molecules such as soluble vascular cell adhesion molecule-1 (sVCAM-1), peptides secreted by endothelial cells such as endothelin-1 (ET-1), and enzymes involved in extracellular matrix remodeling such as a disintegrin and metalloproteinase with thrombospondin motifs-1 (ADAMTS-1) offer a promising alternative. This study aimed to evaluate the correlation between the plasma levels of selected biomarkers and the presence and severity of CAD. We enrolled 40 patients admitted for elective coronary angiography. CAD was defined as having at least one coronary artery stenosis ≥ 50%. The severity of CAD was assessed using the Gensini Score (GS). IL-8 levels were significantly higher in the CAD group, with a mean of 9.78 (SD 0.46) compared to 8.37 (SD 0.40) in the non-CAD group (p = 0.0228). No significant differences were observed for the other biomarkers between the groups. A positive Spearman correlation was found between IL-8 levels and the GS (ρ = 0.39, p = 0.017). These findings suggest that IL-8 may have potential as an additional tool for diagnosing or excluding atherosclerosis. Further studies with larger sample sizes are needed to validate its clinical utility.