Background: Diabetes is a chronic disease which is associated with various micro- and macro-vascular complications. Aim: To evaluate effect of benfotiamine on established markers of oxidative stress in controlled type 2 diabetic population. Materials and method: Open, comparative and non-crossover clinical study was conducted 50 patients with controlled type 2 diabetes mellitus with more than one year duration irrespective of age, sex and their antidiabetic treatment and associated drugs. Patients were put on 200mg of benfotiamine per day and asked to continue antidiabetic therapy already being taken. Patients were regularly evaluated at each visit (during the study) for drug compliance and any adverse effect of benfotiamine. Results: The mean age of the patients was 56.24 ± 10.82 years. The study consisted of 30 males and 20 females. Mean body mass index (BMI) of the patients was 25.05 ± 1.73 kg/m2 irrespective of sex. The mean fasting and postprandial blood sugar levels of the patients were 119.28 ± 24.40 mg/dl and 177.80 ± 37.84 mg/dl respectively at the start of study and HbA1c level was 6.81 ± 0.13% which indicated the controlled status of the patients at start of therapy. Serial blood sugar (fasting and postprandial) estimations were done on each visit to ascertain the controlled status of diabetes. At the end of study (i.e. at 30 days), the mean values of fasting and postprandial blood sugar were 102.82 ± 16.93 mg/dl and 171.32 ± 30.38 mg/dl respectively. These findings indicated that the controlled status of diabetes was maintained throughout the course of study with antidiabetic treatment. Conclusion: Benfotiamine therapy had been found useful in relieving oxidative stress over and above the control of diabetes which may retard development of various micro and macrovascular complications associated with diabetes. It was thus found to be safe and effective therapy.