Keeping this perspective in mind, this study was conducted to assess the prevalence of beta cell dysfunction and low endogenous insulin release diagnosed by low serum C-peptide levels and its correlation with poor glycaemic control as per serum HbA1c, fasting, and post-prandial blood glucose level in patients with type 2 diabetes mellitus on oral anti-diabetic drugs. This evidence concerns the gene INS and type 2 diabetes mellitus.