Diabetic nephropathy (DN) is the main cause of chronic kidney disease, and represents the most common and serious complication of diabetes. The occurrence and progression of DN are closely related to oxidative stress. Excessive reactive oxygen species (ROS) induced by hyperglycemia are involved in direct oxidation and damage of deoxyribonucleic acid (DNA), proteins, and lipids. Glutathione S-transferases have central roles in the cellular detoxification of a diverse group of exogenous and endogenous harmful compounds. The present study aims to clarify the possible role of erythrocyte glutathione S-transferase activity in type 2 diabetic patients with and without nephropathy.  This study included 60 diabetic patients (20 diabetics with normoalbuminuria, 20 diabetics with microalbuminuria, 20 diabetics with macroalbuminuria) and 20 healthy volunteers as a control group. Glutathione S- transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) activities, and Reduced glutathione (GSH) level were significantly lower in diabetic patients with and without nephropathy as compared to control. Malondialdehyde (MDA) level was significantly higher in diabetic patients with and without nephropathy as compared to control. GST, SOD, GPx, CAT, GSH and MDA were positively correlated with estimated glomerular filtration rate and negatively correlated with albumin creatinine ratio. It was concluded that erythrocyte GST may be used as a biomarker to differentiate between different groups of nephropathy.