This study investigates the relationship between cognitive function and oxytocin levels in blood and saliva among male patients with multivessel coronary artery disease (CAD). Existing literature highlights a significant association between CAD and cognitive impairment, with prevalence rates varying widely due to inconsistent diagnostic criteria. Objective: To determine the relationship between cognitive function and oxytocin levels in blood and saliva among patients with multivessel coronary artery disease. Methods: Our research involved 91 male patients undergoing coronary artery bypass grafting, excluding those with concomitant diseases or significant cognitive deficits. Neuropsychological assessments were conducted using validated screening scales, including the Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). Oxytocin levels were measured through enzyme-linked immunosorbent assay (ELISA). Results indicated significant correlations between cognitive performance and oxytocin levels, with direct relationships observed for MMSE and word recall tests, and inverse relationships for the Schulte test. Discussion: These findings suggest that oxytocin may serve as a potential biomarker for vascular cognitive impairment in CAD patients, offering a rapid and objective diagnostic tool that could enhance clinical practice. Conclusion: Ultimately, this study contributes to the understanding of cognitive deficits in CAD and supports the exploration of oxytocin as a diagnostic biomarker.