Background and Objectives: Diabetes mellitus is a common metabolic disease leading to various systemic complications in the affected individuals if not properly controlled with timely interventions. There are various studies showing the toxic effects of high blood glucose and its oxidant derivatives in the pathogenesis of various complications of the disease. Glucose-6– phosphate dehydrogenase (G6PD) is the key enzyme of hexose monophosphate shunt which produces NADPH that protects the body from oxidative damage and prevents from development of various complications. Uncontrolled blood glucose level for a longer duration time diminishes the G6PD activity and can lead the body into complications. This study was conducted in North-East India to evaluate the difference of G6PD activity among diabetics and non-diabetics and to study the impact of hyperglycemia on the G6PD activity.