BACKGROUND: Coronary artery disease (CAD) is a leading cause of death worldwide, caused by environmental factors and characterized by the formation of atherosclerotic plaques. Identification of novel biomarkers is essential for early diagnosis and risk stratification. This study aimed to investigate the expression of DEFA4 and its associated microRNAs in CAD patients and their association with demographic, clinical, and laboratory parameters. METHODS: In this case-control study, 60 CAD patients and 60 healthy controls aged 30 to 75 years were studied to evaluate the expression levels of DEFA4 and related miRNAs in peripheral blood mononuclear cells using real-time PCR. Clinical data, classical risk factors, and laboratory parameters were recorded and statistical analyses were performed using SPSS version 26. RESULTS: DEFA4 expression was increased in CAD patients (3.44 ± 1.36 vs.1.00 ± 0.59), especially in patients with unstable plaques (3.71 ± 1.32) compared to those with stable plaques (2.07 ± 0.40, P < 0.0001). Conversely, the expression of miR-651-5p (0.33 ± 0.13 vs. 1.00 ± 0.72), miR-8080 (0.36 ± 0.39 vs. 1.00 ± 0.35), miR-330-3p (0.55 ± 0.35 vs. 1.00 ± 0.94), miR-298 (0.36 ± 0.39 vs. 1.00 ± 0.53) were significantly decreased. DEFA4 showed a positive correlation with cholesterol (r = 0.821) and neutrophil-lymphocyte ratio (NLR) (r = 0.400), and a negative correlation with hemoglobin (r=-0.855), triglycerides (r=-0.827), and hematocrit (r=-0.850). Bioinformatics analysis through TargetScan and miRDB showed that the target sequences of the studied miRNAs on the 3'UTR region of DEFA4 have high conservation and strong context + scores validating the regulatory hypothesis. However, these strong correlations require external validation in independent cohorts. CONCLUSION: There is an association between increased DEFA4 expression and decreased miRNAs associated with inflammatory markers in CAD patients. However, the case and control groups were not matched for major cardiovascular risk factors, our sample size was limited, and we lacked functional validation. Therefore, these findings indicate an association rather than causation.