Aim: Oxidative stress and free radicals are known to have important roles in the development of atherosclerosis. Malondialdehyde (MDA), a carbonile group produced during lipid peroxidation, is used widely in determining oxidative stress. Nitric Oxide (NO) is a vasodilatator agent derived from the endothelium. The aim of our study was to investigate the relationship between MDA and NO in patient with coronary artery disease. Methods: Forty-five patients diagnosed with 50 % or more stenosis by coronary angiography were included in our study. Patients were separated as 1, 2 and 3 vessel-patients according to the number of vessels affected. Diabetics, smoking patients, patients with malignancy, renal and liver disease, and patients using nitrate preparation were excluded from the study. Fortyfive healthy individuals, who had cardiological evaluation in the last year were identified as the control group. MDA, NO, and lipid measurements were performed accordingly. Results: Serum MDA levels were significantly higher in the CAD group when compared to the controls (p<0.001). No statistical difference was observed in terms of the spread of coronary artery disease and MDA levels. No significant relationship was determined between MDA and NO levels. NO was tended to be higher in the CAD group than the controls (p>0.05). No significant differences were observed in the comparison of NO levels between one, two and three vessel patients. NO levels were significantly higher in hypertensive CAD patients than the normotensive ones (p<0.05). Conclusion: In our study, MDA levels showed highly significant relation with coronary artery disease and NO serum levels were mildly increased in the patient group, however, MDA and NO showed no significant relation. The high MDA levels among all patients with CAD demonstrate a strong relationship between the oxidative stress and the coronary artery disease.