OBJECTIVES:Studies have shown that people with type 2 diabetes mellitus (T2DM) may develop atherosclerosis due to the disturbance in oxidative control and progressive dyslipidemia. Our study aimed to highlight the benefits of simvastatin treatment in improving serum lipids and reducing oxidative damage in patients with T2DM. METHODS:Our randomized control trial included 56 patients with T2DM and dyslipidemia. The participants were on glibenclamide (5mg/day) during the period of the study. The patients were divided into two study groups (groups 1 and 2). Group 1 was the control group and consisted of 31 patients. Group 2 consisted of 25 participants, who were given simvastatin 20mg tablet once daily for 12 weeks. The control group did not receive simvastatin. Both groups were followed-up for measurement of blood pressure, pulse rate, serum lipids, and parameters of oxidative stress. RESULTS:The simvastatin treated group showed a significant improvement with reduced erythrocyte glutathione compared to the control group (p<0.001). This was also associated with a significant reduction in erythrocyte malondialdehyde in the simvastatin treated group compared to the control group (p<0.001). Serum lipids reflected a similar improvement in the levels of erythrocyte malondialdehyde. CONCLUSION:Our study highlights the beneficial role of simvastatin in improving the degree of oxidative stress in patients with T2DM through its effects on serum lipids and lipid peroxidation.