Grape seed proanthocyanidin extract (GSPE) has a broad spectrum of biologic properties against oxidative stress. This study aimed to investigate the effects of GSPE on biochemical factors and antioxidant enzymes of erythrocyte in diabetic rats. Diabetes was induced through single injection of streptozotocin (50 mg.Kg(-1), i.p). Forty Male Sprague-Dawley rats were divided into four Groups: Group 1, healthy control group; Group 2, healthy group treated with GSPE (200 mg.Kg(-1)); Group 3, diabetic control group; Group 4, diabetic group treated with GSPE (200 mg.Kg(-1)) for 4 weeks. At the end, the experimental animals were sacrificed and blood samples were collected and plasma parameters and erythrocytes antioxidant status were evaluated. The results show, treatment with GSPE significantly reduced (P