Resveratrol, a ubiquitous stress-induced phytoalexin, has demonstrated a wide variety of biological activities which make it a good candidate for the treatment of diabetes mellitus. The present study was aimed to evaluate its therapeutic potential by assaying the activities of key enzymes of carbohydrate metabolism in streptozotocin-nicotinamide-induced diabetic rats. The daily oral treatment of resveratrol (5 mg/kg body weight) to diabetic rats for 30 days demonstrated a significant (p<0.05) decline in blood glucose and glycosylated hemoglobin levels and a significant (p<0.05) increase in plasma insulin level. The altered activities of the key enzymes of carbohydrate metabolism such as hexokinase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, glucose-6-phosphate dehydrogenase, glycogen synthase and glycogen phosphorylase in liver and kidney tissues of diabetic rats were significantly (p<0.05) reverted to near normal levels by the administration of resveratrol. Further, resveratrol administration to diabetic rats improved hepatic glycogen content suggesting the antihyperglycemic potential of resveratrol in diabetic rats. The obtained results were compared with glyclazide, a standard oral hypoglycemic drug. Thus, the modulatory effects of resveratrol on attenuating these enzymes activities afford a promise for widespread use for treatment of diabetes in the future.