Cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. Oxidative stress is an independent risk factor by inducing production of oxygen free radicals in cardiovascular diseases. Because a relationship may be hypothesized between Paraoxonase [PON] and Malondialdehyde [MDA], the aim of this study was to investigate the relationship between PON and oxidative stress in patients with non insulin dependent diabetes mellitus [NIDDM] by evaluating MDA concentrations as indexes of oxidative stress. In the present case control study, the levels of total cholesterol, triglycerides and low density lipoprotein were high and the levels of high density lipoprotein were low in the NIDDM patients compared to healthy controls. MDA level was significantly high (p<0.05) and antioxidant activity of PON was significantly low (p<0.05) in patients with NIDDM as compared to controls. Our findings suggest the importance of assessing these markers of oxidative stress and antioxidant capacity of PON along with the other routine investigations in NIDDM patients for initiating the consequences of diabetes leading to coronary artery disease.