This study investigates the antidiabetic activity of Coccinia grandis fruit extract in a streptozotocin (STZ)-induced diabetic rat model, utilizing five groups to assess its efficacy. Wistar albino rats were divided into five groups: Group I (normal control), Group II (diabetic control), Group III (diabetic + glibenclamide at 5mg/kg b.wt./day orally), Group IV (diabetic + Coccinia grandis fruit extract at 250 mg/kg), and Group V (diabetic + Coccinia grandis fruit extract at 250 mg/kg). The extract was administered orally for 28 days, and various parameters including fasting blood glucose levels, Random blood glucose, serum insulin, HbA1c, C-Peptide levels and histopathological changes in pancreatic tissues were evaluated. The results showed a significant reduction in fasting blood glucose levels in Groups III, IV, and V compared to the diabetic control group. Serum insulin and C-Peptide levels were significantly increased in Groups III, IV, and V, indicating improved pancreatic beta-cell function. Treating diabetic rats with Coccinia grandis fruit led to a significant reduction in HbA1C levels. This could be attributed to an improvement in glucose metabolism and glycemic control. Histopathological analysis revealed regeneration of pancreatic beta-cells and improved islet morphology in treated groups. Overall, Coccinia grandis fruit extract showed promising antidiabetic activity, highlighting its potential as a natural alternative for diabetes management