Abstract: Background and Objective: Aged Garlic Extract (AGE), an aqueous extract of ethanol-soaked macerated garlic, contains many of raw garlic’s bioactive components; however, causes considerably fewer physically and socially unpleasant side effects. This study aimed to investigate the antidiabetic and antioxidant potentials of oral intake of AGE (Kyolic, Wakunaga-USA) in streptozotocin (STZ, 60 mg kg–1) induced diabetic rats. Methodology: Diabetic rats (blood sugar >20 mM) were divided into 2 groups and daily given a single oral dose of either normal saline (0.5 mL, control diabetic: C-D) or AGE (600 mg kg–1, AGE-diabetic: AGE-D). Normal rats given normal saline (0.5 mL, C-N) were included for comparison and all treatments were carried out for a period of 8 weeks. Body weight, blood glucose and 24 h food and water intake were measured weekly. Serum, liver and kidney total antioxidants were determined as trolox equivalent antioxidant capacity. Serum insulin, total cholesterol and triglycerides were determined using commercial kits. Catalase was assessed using H2O2 as substrate. Lipid peroxidation was determined by reaction of malondialdenyde (MDA) with thiobarbituric acid. Serum fructosamine and liver protein oxidation were assessed colorimetically. A p<0.05 was considered significant using ANOVA and independent sample t-test. Results: Compared to C-N, the C-D rats showed significant weight loss and decrease in serum insulin and serum, kidney and liver total antioxidants levels and catalase activity (p< 0.05). Concurrently, the C-D rats had elevated food and water intake and urine output, blood glucose, serum cholesterol, triglycerides, fructosamine, MDA levels in kidney and liver and liver protein oxidation. Compared to C-D rats, the orally treated AGE-D rats demonstrated significantly increased body weight and serum insulin (p<0.05) as well as significantly decreased food and water intake, urine output, blood glucose and serum cholesterol, triglycerides and fructosamine (p<0.05). Indicators of oxidative stress were significantly ameliorated in serum, liver and kidneys of AGE-D rats (p<0.05). Conclusion: The data of this study suggested that oral intake of AGE ameliorates oxidative stress and other complications of diabetes in STZ-induced diabetic rats.