Type 2 Diabetes Mellitus (T 2 D M) occurring as a result of reduced insulin action, is seen in a larger section of population. It is also a condition of Oxidative Stress utilizing the antioxidant resources of the body. One such antioxidant is the Paraoxonase1 (PON1) enzyme associated with High Density Lipoprotein. So, the activity of PON1 may be reduced in T 2 D M. Hence, this study was taken up to analyze the status of PON I activity in patients with Type 2 Diabetes Mellitus, attending the Diabetic OP of Sree Balaji Medical College and Hospital (SBMCH). The study included 93 Type 2 Diabetic patients and 89 age and sex matched healthy controls. Paraoxonase 1 activity was assayed by Fluorimetry using the Invitrogen Molecular probes kit. There was a significant reduction in PON1 activity (p value >0.001) along with a decrease in HDL cholesterol among the Type 2 D M patients compared to healthy controls. The progression of Diabetes Mellitus through the years reflected in a much more reduction in PON1 activity as shown by the Pearsons’ correlation analysis. The results were analyzed using SPSS statistical package. It is concluded that Type 2 D M being a condition of Oxidative stress has resulted in the reduction of the antioxidant activity of enzyme PON1.