Abstract: Terminalia bellerica Roxb. is extensively used in Indian traditional systems of medicine to treat various diseases including diabetes mellitus. The present study investigated the antidiabetic effects of Terminalia bellerica fruit extracts and their protective effect in preventing the secondary complications of diabetes mellitus. Hexane, ethylacetate and methanol crude extracts of Terminalia bellerica fruits were administered at the dose of 200, 300 and 300 mg kg-1, respectively, for 60 days to Streptozotocin induced diabetic male Wistar rats. It was found that the fruit extracts significantly (p<0.05) increased the plasma insulin, C-peptide and glucose tolerance levels compared to the diabetic control and the effect was more pronounced in methanol extract treated rats. In addition the plant extracts significantly (p<0.05) increased body weight and serum total protein and significantly decreased the serum levels of total cholesterol, triglycerides, low density lipoprotein cholesterol, urea, uric acid and creatinine in diabetic rats. Thus the results of this experimental study indicated that Terminalia bellerica fruit extracts restored all the biochemical parameters related to the patho-biochemistry of diabetes mellitus and prevented diabetic nephropathy, dyslipidemia and other diabetes-induced complications. These beneficial therapeutic effects of Terminalia bellerica fruits may be due to the synergistic action of more than one bioactive compound and due to the significantly increased C-peptide in extract treated diabetic rats.