Introduction: Diabetes Mellitus is affected by genetic and environmental influences and is characterized by impaired insulin secretion, insulin resistance and chronic hyperglycemia. Vitamin-C levels are typically small for T2DM patients because blood glucose may compete with Vitamin-C for cell absorption due to its structural similarity to the oxidized form and increased oxidant stress may deplete antioxidant stocks. Vitamin-C, an essential micronutrient with potent antioxidant properties, can protect important biomolecules from oxidation by participating in oxidation-reduction reactions and is readily oxidized to dehydroascorbic acid, which is then reduced to ascorbate again. Material and Methods: In this prospective study, 412 patients were included who were diagnosed with T2DM and were randomly divided into two groups of 206 each (the study group and control group). Standard methods for evaluating glycated hemoglobin (HbA1c) have been used in ETDA(Ethylenediaminetetraacetic acid) blood. Glucose for fasting was measured in blood. Vitamin-C and placebo were administered to patients for three weeks at a time. During follow up, patients were advised to bring unused drugs and containers. All patients had their regular dietary pattern preserved through constraining their intake of foods, which are rich in Vitamin-C. Results: There were total 206 patients were included as study group and control group, respectively. 123 were males among 206 patients in Vitamin-C group while 83 were females. In control group 120 were males and 86 were females among 206 controls. The mean age of cases in Vitamin-C group is noted to be 45.77 __ampersandsignplusmn; 7.66 while in control group it is 43.33 __ampersandsignplusmn; 5.64. The mean post meal blood sugar has significantly decreased in cases administered with Vitamin-C compared to controls. In group, B saw a significant decrease in fasting blood sugar levels and HbA1c. Plasma Vitamin-C levels had a significant increase in study group. Conclusion: Vitamin-C supplementation can substantially reduce level of HbA1c as well as blood glucose in T2DM patients.