<b><i>Introduction:</i></b> Atherosclerosis is a chronic inflammatory process maintained during all stages of the disease by several proinflammatory mediators, such as cytokines and chemokines. Interleukin (IL)-36 cytokines are proinflammatory and have an essential role in innate and adaptive immunity, but the role of IL-36 has not been determined in coronary artery disease (CAD). This study aimed to measure the serum levels of IL-36 in patients with CAD and their association with the serum levels of tumor necrosis factor (TNF)-α, IL-6, and IL-32 and also investigate their correlation with the serum levels of malondialdehyde (MDA) and ferric reducing antioxidant power (FRAP). <b><i>Methods:</i></b> A total of 168 subjects (84 CAD and 84 control subjects) were examined in this research. The total serum levels of IL-36 were measured using the enzyme-linked immunosorbent assay (ELISA). Also, some oxidative stress parameters were evaluated by FRAP and MDA assays in the serum. <b><i>Results:</i></b> The serum levels of IL-36 and MDA were significantly higher, and FRAP was significantly lower in the CAD group compared to the controls. Furthermore, the serum levels of IL-36, MDA, and FRAP significantly correlated with the CAD group’s cardiac arterial stenosis. Also, the serum levels of IL-36 had a positive and significant correlation with the serum levels of TNF-α, IL-6, IL-32, and biochemical parameters in the CAD group. <b><i>Conclusion:</i></b> Higher serum levels of IL-36 and its association with the serum levels of TNF-α, IL-32, and IL-6 may play a key role in the pathogenesis of CAD, leading to an increased risk of clogged arteries and oxidative stress.