Objective: To assess the safety and efficacy of herbal formulation rich in standardized fenugreek seed extract (IND-2) add-on therapy in type 2 diabetes mellitus (T2DM) patients who were on insulin treatment in prospective, single arm, open-label, uncontrolled, multicentre trial. Methods: T2DM patients (n=30) with aged 18-80 years who were stabilized on insulin treatment with fasting blood sugar (FBS) level between 100-140 mg/dL received IND-2 capsules (700 mg, thrice a day) for 16 weeks. The primary endpoints were an assessment of FBS at week 2, 4, 6, 8, 12 and 16. Secondary endpoints include post-prandial blood sugar level, glycosylated Hb (HbA1c), reduction in the dose of insulin and number of hypoglycemic attacks, and improvement in lipid profile at various weeks. Safety and adverse events (AEs) were also assessed during the study. Results: Study was completed in twenty T2DM patients, and there was no significant reduction in FBS and post-prandial blood sugar level after add-on therapy of IND-2. However, add-on therapy of IND-2 significantly reduced (P<0.01) the HbA1c values, requirements of insulin and hypoglycemic events as compared with baseline. Total cholesterol, high-density lipoproteins-cholesterol, and low-density lipoprotein-cholesterol levels were significantly increased (P<0.01) after IND-2 add-on therapy. Body weight and safety outcomes did not differ significantly in IND-2 add-on therapy group at week 16. Additionally, add-on therapy of IND-2 did not produce any serious adverse events. Conclusions: The results of present investigation suggest that add-on therapy of IND-2 with insulin in T2DM patients improves glycaemic control through a decrease in levels of HbA1c and number of insulin doses needed per day without an increase in body weight and risk of hypoglycemia. Thus, IND-2 may provide a safe and well-tolerated add-on therapy option for the management of T2DM.