Resveratrol is a polyphenolic phytoalexin produced in appreciable amounts as a secondary metabolite in grapevines in response to fungal infections. Based on the present knowledge, it appears to be a promising bioactive natural molecule with potential applications in phytotherapy or pharmacology. The present study was aimed to evaluate the antidiabetic properties of resveratrol in streptozotocin-nicotinamide induced experimental diabetes in rats. The diabetic rats orally treated with resveratrol (5 mg kg(-)(1)b.w d(-)(1)) for 30 days resulted in significant (p<0.05) decrease in the levels of blood glucose, glycosylated hemoglobin, blood urea, serum uric acid, serum creatinine and diminished activities of pathophysiological enzymes such as aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). The antihyperglycemic nature of resveratrol is also evidenced from the improvement in the levels of plasma insulin and hemoglobin. Further, the results are comparable with glyclazide, an oral standard drug. Thus, the present findings suggest that resveratrol may be considered as an effective therapeutic agent for the treatment of diabetes mellitus.